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1.
Blood ; 143(20): 2059-2072, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38437498

RESUMO

ABSTRACT: BRG1 (SMARCA4) and BRM (SMARCA2) are the mutually exclusive core ATPases of the chromatin remodeling BAF (BRG1/BRM-associated factor) complexes. They enable transcription factors/cofactors to access enhancers/promoter and modulate gene expressions responsible for cell growth and differentiation of acute myeloid leukemia (AML) stem/progenitor cells. In AML with MLL1 rearrangement (MLL1r) or mutant NPM1 (mtNPM1), although menin inhibitor (MI) treatment induces clinical remissions, most patients either fail to respond or relapse, some harboring menin mutations. FHD-286 is an orally bioavailable, selective inhibitor of BRG1/BRM under clinical development in AML. Present studies show that FHD-286 induces differentiation and lethality in AML cells with MLL1r or mtNPM1, concomitantly causing perturbed chromatin accessibility and repression of c-Myc, PU.1, and CDK4/6. Cotreatment with FHD-286 and decitabine, BET inhibitor (BETi) or MI, or venetoclax synergistically induced in vitro lethality in AML cells with MLL1r or mtNPM1. In models of xenografts derived from patients with AML with MLL1r or mtNPM1, FHD-286 treatment reduced AML burden, improved survival, and attenuated AML-initiating potential of stem-progenitor cells. Compared with each drug, cotreatment with FHD-286 and BETi, MI, decitabine, or venetoclax significantly reduced AML burden and improved survival, without inducing significant toxicity. These findings highlight the FHD-286-based combinations as a promising therapy for AML with MLL1r or mtNPM1.


Assuntos
DNA Helicases , Leucemia Mieloide Aguda , Proteínas Nucleares , Proteínas Proto-Oncogênicas , Fatores de Transcrição , Animais , Humanos , Camundongos , Proteínas que Contêm Bromodomínio , Linhagem Celular Tumoral , DNA Helicases/antagonistas & inibidores , DNA Helicases/genética , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/genética , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Células-Tronco Neoplásicas/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nucleofosmina , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Ensaios Antitumorais Modelo de Xenoenxerto
2.
Dev Biol ; 461(2): 132-144, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32044379

RESUMO

The formation of the craniofacial skeleton is a highly dynamic process that requires proper orchestration of various cellular processes in cranial neural crest cell (cNCC) development, including cell migration, proliferation, differentiation, polarity and cell death. Alterations that occur during cNCC development result in congenital birth defects and craniofacial abnormalities such as cleft lip with or without cleft palate. While the gene regulatory networks facilitating neural crest development have been extensively studied, the epigenetic mechanisms by which these pathways are activated or repressed in a temporal and spatially regulated manner remain largely unknown. Chromatin modifiers can precisely modify gene expression through a variety of mechanisms including histone modifications such as methylation. Here, we investigated the role of two members of the PRDM (Positive regulatory domain) histone methyltransferase family, Prdm3 and Prdm16 in craniofacial development using genetic models in zebrafish and mice. Loss of prdm3 or prdm16 in zebrafish causes craniofacial defects including hypoplasia of the craniofacial cartilage elements, undefined posterior ceratobranchials, and decreased mineralization of the parasphenoid. In mice, while conditional loss of Prdm3 in the early embryo proper causes mid-gestation lethality, loss of Prdm16 caused craniofacial defects including anterior mandibular hypoplasia, clefting in the secondary palate and severe middle ear defects. In zebrafish, prdm3 and prdm16 compensate for each other as well as a third Prdm family member, prdm1a. Combinatorial loss of prdm1a, prdm3, and prdm16 alleles results in severe hypoplasia of the anterior cartilage elements, abnormal formation of the jaw joint, complete loss of the posterior ceratobranchials, and clefting of the ethmoid plate. We further determined that loss of prdm3 and prdm16 reduces methylation of histone 3 lysine 9 (repression) and histone 3 lysine 4 (activation) in zebrafish. In mice, loss of Prdm16 significantly decreased histone 3 lysine 9 methylation in the palatal shelves but surprisingly did not change histone 3 lysine 4 methylation. Taken together, Prdm3 and Prdm16 play an important role in craniofacial development by maintaining temporal and spatial regulation of gene regulatory networks necessary for proper cNCC development and these functions are both conserved and divergent across vertebrates.


Assuntos
Anormalidades Craniofaciais/genética , Proteínas de Ligação a DNA/fisiologia , Histona Metiltransferases/fisiologia , Proteína do Locus do Complexo MDS1 e EVI1/fisiologia , Crânio/embriologia , Fatores de Transcrição/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Animais , Cromatina/genética , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Orelha Média/anormalidades , Orelha Média/embriologia , Ossos Faciais/embriologia , Feminino , Genes Letais , Código das Histonas/genética , Histona Metiltransferases/deficiência , Histona Metiltransferases/genética , Histonas/metabolismo , Arcada Osseodentária/embriologia , Proteína do Locus do Complexo MDS1 e EVI1/deficiência , Proteína do Locus do Complexo MDS1 e EVI1/genética , Masculino , Metilação , Camundongos Endogâmicos C57BL , Processamento de Proteína Pós-Traducional/genética , Especificidade da Espécie , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/deficiência , Proteínas de Peixe-Zebra/genética
3.
Genome ; 64(4): 372-385, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33395363

RESUMO

The COVID-19 pandemic is one of the most significant public health threats in recent history and has impacted the lives of almost everyone worldwide. Epigenetic mechanisms contribute to many aspects of the SARS-CoV-2 replication cycle, including expression levels of viral receptor ACE2, expression of cytokine genes as part of the host immune response, and the implication of various histone modifications in several aspects of COVID-19. SARS-CoV-2 proteins physically associate with many different host proteins over the course of infection, and notably there are several interactions between viral proteins and epigenetic enzymes such as HDACs and bromodomain-containing proteins as shown by correlation-based studies. The many contributions of epigenetic mechanisms to the viral life cycle and the host immune response to infection have resulted in epigenetic factors being identified as emerging biomarkers for COVID-19, and project epigenetic modifiers as promising therapeutic targets to combat COVID-19. This review article highlights the major epigenetic pathways at play during COVID-19 disease and discusses ongoing clinical trials that will hopefully contribute to slowing the spread of SARS-CoV-2.


Assuntos
COVID-19/genética , COVID-19/virologia , Epigênese Genética , SARS-CoV-2/fisiologia , Enzima de Conversão de Angiotensina 2/genética , Citrulinação , Citocinas/genética , Metilação de DNA , Histonas/química , Humanos , Pandemias
4.
Biochem Cell Biol ; 98(6): 631-646, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32706995

RESUMO

Pulmonary arterial hypertension (PAH) is a devastating disease of the cardiopulmonary system caused by the narrowing of the pulmonary arteries, leading to increased vascular resistance and pressure. This leads to right ventricle remodeling, dysfunction, and eventually, death. While conventional therapies have largely focused on targeting vasodilation, other pathological features of PAH including aberrant inflammation, mitochondrial dynamics, cell proliferation, and migration have not been well explored. Thus, despite some recent improvements in PAH treatment, the life expectancy and quality of life for patients with PAH remains poor. Showing many similarities to cancers, PAH is characterized by increased pulmonary arterial smooth muscle cell proliferation, decreased apoptotic signaling pathways, and changes in metabolism. The recent successes of therapies targeting epigenetic modifiers for the treatment of cancer has prompted epigenetic research in PAH, revealing many new potential therapeutic targets. In this minireview we discuss the emergence of epigenetic dysregulation in PAH and highlight epigenetic-targeting compounds that may be effective for the treatment of PAH.


Assuntos
Epigênese Genética , Genoma Humano , Pulmão/metabolismo , Hipertensão Arterial Pulmonar , Artéria Pulmonar/metabolismo , Qualidade de Vida , Animais , Apoptose , Humanos , Inflamação/genética , Inflamação/metabolismo , Inflamação/terapia , Pulmão/patologia , Hipertensão Arterial Pulmonar/genética , Hipertensão Arterial Pulmonar/metabolismo , Hipertensão Arterial Pulmonar/terapia , Transdução de Sinais
5.
Nucleic Acids Res ; 42(15): 9892-907, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25114048

RESUMO

Rrd1p (resistance to rapamycin deletion 1) has been previously implicated in controlling transcription of rapamycin-regulated genes in response to rapamycin treatment. Intriguingly, we show here that Rrd1p associates with the coding sequence of a galactose-inducible and rapamycin non-responsive GAL1 gene, and promotes the association of RNA polymerase II with GAL1 in the absence of rapamycin treatment following transcriptional induction. Consistently, nucleosomal disassembly at GAL1 is impaired in the absence of Rrd1p, and GAL1 transcription is reduced in the Δrrd1 strain. Likewise, Rrd1p associates with the coding sequences of other rapamycin non-responsive and inducible GAL genes to promote their transcription in the absence of rapamycin treatment. Similarly, inducible, but rapamycin-responsive, non-GAL genes such as CTT1, STL1 and CUP1 are also regulated by Rrd1p. However, transcription of these inducible GAL and non-GAL genes is not altered in the absence of Rrd1p when the steady-state is reached after long transcriptional induction. Consistently, transcription of the constitutively active genes is not changed in the Δrrd1 strain. Taken together, our results demonstrate a new function of Rrd1p in stimulation of initial rounds of transcription, but not steady-state/constitutive transcription, of both rapamycin-responsive and non-responsive genes independently of rapamycin treatment.


Assuntos
Regulação Fúngica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptidilprolil Isomerase/metabolismo , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Sirolimo/farmacologia , Ativação Transcricional , Galactoquinase/genética , Regiões Promotoras Genéticas , Proteínas de Saccharomyces cerevisiae/genética , Transativadores/genética , Iniciação da Transcrição Genética , Transcrição Gênica
6.
J Biol Chem ; 288(2): 793-806, 2013 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-23188830

RESUMO

Rad14p is a DNA damage recognition factor in nucleotide excision repair. Intriguingly, we show here that Rad14p associates with the promoter of a galactose-inducible GAL1 gene after transcriptional induction in the absence of DNA lesion. Such an association of Rad14p facilitates the recruitment of TBP, TFIIH, and RNA polymerase II to the GAL1 promoter. Furthermore, the association of RNA polymerase II with the GAL1 promoter is significantly decreased in the absence of Rad14p, when the coding sequence was deleted. These results support the role of Rad14p in transcriptional initiation. Consistently, the level of GAL1 mRNA is significantly decreased in the absence of Rad14p. Similar results are also obtained at other galactose-inducible GAL genes such as GAL7 and GAL10. Likewise, Rad14p promotes transcription of other non-GAL genes such as CUP1, CTT1, and STL1 after transcriptional induction. However, the effect of Rad14p on the steady-state levels of transcription of GAL genes or constitutively active genes such as ADH1, PGK1, PYK1, and RPS5 is not observed. Thus, Rad14p promotes initial transcription but does not appear to regulate the steady-state level. Collectively, our results unveil a new role of Rad14p in stimulating transcription in addition to its well-known function in nucleotide excision repair.


Assuntos
Dano ao DNA , Enzimas Reparadoras do DNA/fisiologia , Reparo do DNA/fisiologia , Regulação Fúngica da Expressão Gênica/genética , Proteínas de Saccharomyces cerevisiae/fisiologia , Transcrição Gênica/genética , Sequência de Bases , Imunoprecipitação da Cromatina , Primers do DNA , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas
7.
J Biol Chem ; 288(14): 9619-9633, 2013 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-23417674

RESUMO

H2B ubiquitylation is carried out by Bre1p, an E3 ligase, along with an E2 conjugase, Rad6p. H2B ubiquitylation has been previously implicated in promoting the association of RNA polymerase II with the coding sequence of the active GAL1 gene, and hence transcriptional elongation. Intriguingly, we find here that the association of RNA polymerase II with the active GAL1 coding sequence is not decreased in Δbre1, although it is required for H2B ubiquitylation. In contrast, the loss of Rad6p significantly impairs the association of RNA polymerase II with GAL1. Likewise, the point mutation of lysine 123 (ubiquitylation site) to arginine of H2B (H2B-K123R) also lowers the association of RNA polymerase II with GAL1, consistent with the role of H2B ubiquitylation in promoting RNA polymerase II association. Surprisingly, unlike the Δrad6 and H2B-K123R strains, complete deletion of BRE1 does not impair the association of RNA polymerase II with GAL1. However, deletion of the RING domain of Bre1p (that is essential for H2B ubiquitylation) impairs RNA polymerase II association with GAL1. These results imply that a non-RING domain of Bre1p counteracts the stimulatory role of the RING domain in regulating the association of RNA polymerase II with GAL1, and hence RNA polymerase II occupancy is not impaired in Δbre1. Consistently, GAL1 transcription is impaired in the absence of the RING domain of Bre1p, but not in Δbre1. Similar results are also obtained at other genes. Collectively, our results implicate both the stimulatory and repressive roles of Bre1p in regulation of RNA polymerase II association with active genes (and hence transcription) in vivo.


Assuntos
Histonas/química , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/enzimologia , Ubiquitina-Proteína Ligases/química , Ubiquitina/química , Imunoprecipitação da Cromatina , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Mutação , Proteínas Nucleares/metabolismo , Fases de Leitura Aberta , Plasmídeos/metabolismo , Mutação Puntual , Estrutura Terciária de Proteína , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Transcrição Gênica , Ubiquitina-Proteína Ligases/metabolismo
8.
J Dev Biol ; 12(1)2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38390960

RESUMO

Developmental biology is intricately regulated by epigenetics and metabolism but the mechanisms are not completely understood. The situation becomes even more complicated during diseases where all three phenomena are dysregulated. A salient example is COVID-19, where the death toll exceeded 6.96 million in 4 years, while the virus continues to mutate into different variants and infect people. Early evidence during the pandemic showed that the host's immune and inflammatory responses to COVID-19 (like the cytokine storm) impacted the host's metabolism, causing damage to the host's organs and overall physiology. The involvement of angiotensin-converting enzyme 2 (ACE2), the pivotal host receptor for the SARS-CoV-2 virus, was identified and linked to epigenetic abnormalities along with other contributing factors. Recently, studies have revealed stronger connections between epigenetics and metabolism in COVID-19 that impact development and accelerate aging. Patients manifest systemic toxicity, immune dysfunction and multi-organ failure. Single-cell multiomics and other state-of-the-art high-throughput studies are only just beginning to demonstrate the extent of dysregulation and damage. As epigenetics and metabolism directly impact development, there is a crucial need for research implementing cutting-edge technology, next-generation sequencing, bioinformatics analysis, the identification of biomarkers and clinical trials to help with prevention and therapeutic interventions against similar threats in the future.

9.
J Biol Chem ; 287(43): 36414-22, 2012 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-22910905

RESUMO

Previous studies have demonstrated transcription-coupled nucleotide/base excision repair. We report here for the first time that DNA double-strand break (DSB) repair is also coupled to transcription. We generated a yeast strain by introducing a homing (Ho) endonuclease cut site followed by a nucleotide sequence for multiple Myc epitopes at the 3' end of the coding sequence of a highly active gene, ADH1. This yeast strain also contains the Ho cut site at the nearly silent or poorly active mating type α (MATα) locus and expresses Ho endonuclease under the galactose-inducible GAL1 promoter. Using this strain, DSBs were generated at the ADH1 and MATα loci in galactose-containing growth medium that induced HO expression. Subsequently, yeast cells were transferred to dextrose-containing growth medium to stop HO expression, and the DSB repair was monitored at the ADH1 and MATα loci by PCR, using the primer pairs flanking the Ho cut sites. Our results revealed a faster DSB repair at the highly active ADH1 than that at the nearly silent MATα locus, hence implicating a transcription-coupled DSB repair at the active gene in vivo. Subsequently, we extended this study to another gene, PHO5 (carrying the Ho cut site at its coding sequence), under transcriptionally active and inactive growth conditions. We found a fast DSB repair at the active PHO5 gene in comparison to its inactive state. Collectively, our results demonstrate a preferential DSB repair at the active gene, thus supporting transcription-coupled DSB repair in living cells.


Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA/fisiologia , DNA Fúngico/metabolismo , Saccharomyces cerevisiae/metabolismo , Fosfatase Ácida/genética , Fosfatase Ácida/metabolismo , Álcool Desidrogenase/genética , Álcool Desidrogenase/metabolismo , DNA Fúngico/genética , Desoxirribonucleases de Sítio Específico do Tipo II/genética , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Loci Gênicos/fisiologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
10.
Epigenomes ; 6(2)2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35645252

RESUMO

Although few in number, studies on epigenome of the heart of COVID-19 patients show that epigenetic signatures such as DNA methylation are significantly altered, leading to changes in expression of several genes. It contributes to pathogenic cardiac phenotypes of COVID-19, e.g., low heart rate, myocardial edema, and myofibrillar disarray. DNA methylation studies reveal changes which likely contribute to cardiac disease through unknown mechanisms. The incidence of severe COVID-19 disease, including hospitalization, requiring respiratory support, morbidity, and mortality, is disproportionately higher in individuals with co-morbidities. This poses unprecedented strains on the global healthcare system. While their underlying conditions make patients more susceptible to severe COVID-19 disease, strained healthcare systems, lack of adequate support, or sedentary lifestyles from ongoing lockdowns have proved detrimental to their underlying health conditions, thus pushing them to severe risk of congenital heart disease (CHD) itself. Prophylactic vaccines against COVID-19 have ushered new hope for CHD. A common connection between COVID-19 and CHD is SARS-CoV-2's host receptor ACE2, because ACE2 regulates and protects organs, including the heart, in various ways. ACE2 is a common therapeutic target against cardiovascular disease and COVID-19 which damages organs. Hence, this review explores the above regarding CHDs, cardiovascular damage, and cardiac epigenetics, in COVID-19 patients.

11.
Mol Cell Biol ; 42(1): e0036821, 2022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-34661445

RESUMO

San1 ubiquitin ligase is involved in nuclear protein quality control via its interaction with intrinsically disordered proteins for ubiquitylation and proteasomal degradation. Since several transcription/chromatin regulatory factors contain intrinsically disordered domains and can be inhibitory to transcription when in excess, San1 might be involved in transcription regulation. To address this, we analyzed the role of San1 in the genome-wide association of TATA box binding protein (TBP; which nucleates preinitiation complex [PIC] formation for transcription initiation) and RNA polymerase II (Pol II). Our results reveal the roles of San1 in regulating TBP recruitment to the promoters and Pol II association with the coding sequences and, hence, PIC formation and coordination of elongating Pol II, respectively. Consistently, transcription is altered in the absence of San1. Such transcriptional alteration is associated with impaired ubiquitylation and proteasomal degradation of Spt16 and gene association of Paf1 but not the incorporation of centromeric histone, Cse4, into the active genes in the Δsan1 strain. Collectively, our results demonstrate distinct functions of a nuclear protein quality control factor in regulating the genome-wide PIC formation and elongating Pol II (and hence transcription), thus unraveling new gene regulatory mechanisms.


Assuntos
RNA Polimerase II/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Estudo de Associação Genômica Ampla/métodos , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
12.
J Dev Biol ; 9(2)2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-34065783

RESUMO

Epigenetic modifications regulate gene expression for development, immune response, disease, and other processes. A major role of epigenetics is to control the dynamics of chromatin structure, i.e., the condensed packaging of DNA around histone proteins in eukaryotic nuclei. Key epigenetic factors include enzymes for histone modifications and DNA methylation, non-coding RNAs, and prions. Epigenetic modifications are heritable but during embryonic development, most parental epigenetic marks are erased and reset. Interestingly, some epigenetic modifications, that may be resulting from immune response to stimuli, can escape remodeling and transmit to subsequent generations who are not exposed to those stimuli. This phenomenon is called transgenerational epigenetic inheritance if the epigenetic phenotype persists beyond the third generation in female germlines and second generation in male germlines. Although its primary function is likely immune response for survival, its role in the development and functioning of the immune system is not extensively explored, despite studies reporting transgenerational inheritance of stress-induced epigenetic modifications resulting in immune disorders. Hence, this review draws from studies on transgenerational epigenetic inheritance, immune system development and function, high-throughput epigenetics tools to study those phenomena, and relevant clinical trials, to focus on their significance and deeper understanding for future research, therapeutic developments, and various applications.

13.
J Dev Biol ; 9(4)2021 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-34698193

RESUMO

Heart disease is the leading cause of death in the United States and worldwide. Understanding the molecular mechanisms of cardiac development and regeneration will improve diagnostic and therapeutic interventions against heart disease. In this direction, zebrafish is an excellent model because several processes of zebrafish heart development are largely conserved in humans, and zebrafish has several advantages as a model organism. Zebrafish transcriptomic profiles undergo alterations during different stages of cardiac development and regeneration which are revealed by RNA-sequencing. ChIP-sequencing has detected genome-wide occupancy of histone post-translational modifications that epigenetically regulate gene expression and identified a locus with enhancer-like characteristics. ATAC-sequencing has identified active enhancers in cardiac progenitor cells during early developmental stages which overlap with occupancy of histone modifications of active transcription as determined by ChIP-sequencing. CRISPR-mediated editing of the zebrafish genome shows how chromatin modifiers and DNA-binding proteins regulate heart development, in association with crucial signaling pathways. Hence, more studies in this direction are essential to improve human health because they answer fundamental questions on cardiac development and regeneration, their differences, and why zebrafish hearts regenerate upon injury, unlike humans. This review focuses on some of the latest studies using state-of-the-art technology enabled by the elegant yet simple zebrafish.

14.
J Dev Biol ; 9(4)2021 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-34940501

RESUMO

With over 4.8 million deaths within 2 years, time is of the essence in combating COVID-19. The infection now shows devastating impacts on the younger population, who were not previously predicted to be vulnerable, such as in the older population. COVID-19-related complications have been reported in neonates whose mothers were infected with SARS-CoV-2 during pregnancy, and in children who get infected. Hence, a deeper understanding of the pathophysiology of COVID-19 during various developmental stages and placental transmission is essential. Although a connection has not yet been established between exosomal trafficking and the placental transmission of COVID-19, reports indicate that SARS-CoV-2 components may be trafficked between cells through exosomes. As the infection spreads, the transcriptome of cells is drastically perturbed, e.g., through the severe upregulation of several immune-related genes. Consequently, a major outcome of COVID-19 is an elevated immune response and the detection of viral RNA transcripts in host tissue. In this direction, this review focuses on SARS-CoV-2 virology, its in utero transmission from infected pregnant mothers to fetuses, SARS-CoV-2 and exosomal cellular trafficking, transcriptomic impacts, and RNA-mediated therapeutics against COVID-19. Future research will establish stronger connections between the above processes to develop diagnostic and therapeutic solutions towards COVID-19 and similar viral outbreaks.

15.
Mol Cell Biol ; 40(7)2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-31932480

RESUMO

Although an F-box protein, Mdm30, is found to regulate ubiquitylation of the Sub2 component of TREX (transcription-export) complex for proteasomal degradation in stimulation of mRNA export, it remains unknown whether such ubiquitin-proteasome system (UPS) regulation of Sub2 occurs cotranscriptionally via its interaction with Mdm30. Further, it is unclear whether impaired UPS regulation of Sub2 in the absence of Mdm30 alters mRNA export via splicing defects of export factors and/or mitochondrial dynamics/function, since Sub2 controls mRNA splicing and Mdm30 regulates mitochondrial aggregation. Here, we show that Mdm30 interacts with Sub2, and temporary shutdown of Mdm30 enhances Sub2's abundance and impairs mRNA export. Likewise, Sub2's abundance is increased following transcriptional inhibition. These results support Mdm30's direct role in regulation of Sub2's cellular abundance in a transcription-dependent manner. Consistently, the chromatin-bound Sub2 level is increased in the absence of Mdm30. Further, we find that Mdm30 does not facilitate splicing of export factors. Moreover, Mdm30 does not have a dramatic effect on mitochondrial respiration/function, and mRNA export occurs in the absence of Fzo1, which is required for mitochondrial dynamics/respiration. Collective results reveal that Mdm30 interacts with Sub2 for proteasomal degradation in a transcription-dependent manner to promote mRNA export independently of splicing or mitochondrial function, thus advancing our understanding of mRNA export.


Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Adenosina Trifosfatases/metabolismo , Proteínas F-Box/metabolismo , Mitocôndrias/fisiologia , RNA Mensageiro/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Adenosina Trifosfatases/genética , GTP Fosfo-Hidrolases/genética , Proteínas de Membrana/genética , Dinâmica Mitocondrial/genética , Proteínas Mitocondriais/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Splicing de RNA , Transporte de RNA , RNA Mensageiro/genética , Saccharomyces cerevisiae , Proteínas de Saccharomyces cerevisiae/genética , Transcrição Gênica/genética , Ubiquitinação
16.
Mol Cell Biol ; 39(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30745412

RESUMO

Cap-binding complex (CBC) associates cotranscriptionally with the cap structure at the 5' end of nascent mRNA to protect it from exonucleolytic degradation. Here, we show that CBC promotes the targeting of an mRNA export adaptor, Yra1 (forming transcription export [TREX] complex with THO and Sub2), to the active genes and enhances mRNA export in Saccharomyces cerevisiae Likewise, recruitment of Npl3 (an hnRNP involved in mRNA export via formation of export-competent ribonuclear protein complex [RNP]) to the active genes is facilitated by CBC. Thus, CBC enhances targeting of the export factors and promotes mRNA export. Such function of CBC is not mediated via THO and Sub2 of TREX, cleavage and polyadenylation factors, or Sus1 (that regulates mRNA export via transcription export 2 [TREX-2]). However, CBC promotes splicing of SUS1 mRNA and, consequently, Sus1 protein level and mRNA export via TREX-2. Collectively, our results support the hypothesis that CBC promotes recruitment of Yra1 and Npl3 to the active genes, independently of THO, Sub2, or cleavage and polyadenylation factors, and enhances mRNA export via TREX and RNP, respectively, in addition to its role in facilitating SUS1 mRNA splicing to increase mRNA export through TREX-2, revealing distinct stimulatory functions of CBC in mRNA export.


Assuntos
Complexo Proteico Nuclear de Ligação ao Cap/metabolismo , Proteínas de Ligação ao Cap de RNA/metabolismo , RNA Mensageiro/metabolismo , Transporte Ativo do Núcleo Celular/genética , Transporte Ativo do Núcleo Celular/fisiologia , Complexo Proteico Nuclear de Ligação ao Cap/genética , Proteínas Nucleares/metabolismo , Splicing de RNA , Transporte de RNA/fisiologia , RNA Mensageiro/genética , Proteínas de Ligação a RNA/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica/genética , Fatores de Poliadenilação e Clivagem de mRNA/metabolismo
17.
Genetics ; 208(1): 191-205, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29141908

RESUMO

SAGA (Spt-Ada-Gcn5-Acetyltransferase) and TFIID (transcription factor IID) have been previously shown to facilitate the formation of the PIC (pre-initiation complex) at the promoters of two distinct sets of genes. Here, we demonstrate that TFIID and SAGA differentially participate in the stimulation of PIC formation (and hence transcriptional initiation) at the promoter of PHO84, a gene for the high-affinity inorganic phosphate (Pi) transporter for crucial cellular functions, in response to nutrient signaling. We show that transcriptional initiation of PHO84 occurs predominantly in a TFIID-dependent manner in the absence of Pi in the growth medium. Such TFIID dependency is mediated via the NuA4 (nucleosome acetyltransferase of H4) histone acetyltransferase (HAT). Intriguingly, transcriptional initiation of PHO84 also occurs in the presence of Pi in the growth medium, predominantly via the SAGA complex, but independently of NuA4 HAT. Thus, Pi in the growth medium switches transcriptional initiation of PHO84 from NuA4-TFIID to SAGA dependency. Further, we find that both NuA4-TFIID- and SAGA-dependent transcriptional initiations of PHO84 are facilitated by the 19S proteasome subcomplex or regulatory particle (RP) via enhanced recruitment of the coactivators SAGA and NuA4 HAT, which promote TFIID-independent and -dependent PIC formation for transcriptional initiation, respectively. NuA4 HAT does not regulate activator binding to PHO84, but rather facilitates PIC formation for transcriptional initiation in the absence of Pi in the growth medium. On the other hand, SAGA promotes activator recruitment to PHO84 for transcriptional initiation in the growth medium containing Pi. Collectively, our results demonstrate two distinct stimulatory pathways for PIC formation (and hence transcriptional initiation) at PHO84 by TFIID, SAGA, NuA4, and 19S RP in the presence and absence of an essential nutrient, Pi, in the growth media, thus providing new regulatory mechanisms of transcriptional initiation in response to nutrient signaling.


Assuntos
Regulação da Expressão Gênica , Fenômenos Fisiológicos da Nutrição/genética , Ativação Transcricional , Meios de Cultura , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Regiões Promotoras Genéticas , Simportadores de Próton-Fosfato/genética , Simportadores de Próton-Fosfato/metabolismo , Transdução de Sinais , Leveduras/genética , Leveduras/metabolismo
18.
J Dev Biol ; 6(4)2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-30424580

RESUMO

Cranial neural crest cells undergo cellular growth, patterning, and differentiation within the branchial arches to form cartilage and bone, resulting in a precise pattern of skeletal elements forming the craniofacial skeleton. However, it is unclear how cranial neural crest cells are regulated to give rise to the different shapes and sizes of the bone and cartilage. Epigenetic regulators are good candidates to be involved in this regulation, since they can exert both broad as well as precise control on pattern formation. Here, we investigated the role of the histone acetyltransferases Kat2a and Kat2b in craniofacial development using TALEN/CRISPR/Cas9 mutagenesis in zebrafish and the Kat2ahat/hat (also called Gcn5) allele in mice. kat2a and kat2b are broadly expressed during embryogenesis within the central nervous system and craniofacial region. Single and double kat2a and kat2b zebrafish mutants have an overall shortening and hypoplastic nature of the cartilage elements and disruption of the posterior ceratobranchial cartilages, likely due to smaller domains of expression of both cartilage- and bone-specific markers, including sox9a and col2a1, and runx2a and runx2b, respectively. Similarly, in mice we observe defects in the craniofacial skeleton, including hypoplastic bone and cartilage and altered expression of Runx2 and cartilage markers (Sox9, Col2a1). In addition, we determined that following the loss of Kat2a activity, overall histone 3 lysine 9 (H3K9) acetylation, the main epigenetic target of Kat2a/Kat2b, was decreased. These results suggest that Kat2a and Kat2b are required for growth and differentiation of craniofacial cartilage and bone in both zebrafish and mice by regulating H3K9 acetylation.

19.
Mol Cell Biol ; 37(13)2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28396559

RESUMO

We have recently demonstrated that an mRNA capping enzyme, Cet1, impairs promoter-proximal accumulation/pausing of RNA polymerase II (Pol II) independently of its capping activity in Saccharomyces cerevisiae to control transcription. However, it is still unknown how Pol II pausing is regulated by Cet1. Here, we show that Cet1's N-terminal domain (NTD) promotes the recruitment of FACT (facilitates chromatin transcription that enhances the engagement of Pol II into transcriptional elongation) to the coding sequence of an active gene, ADH1, independently of mRNA-capping activity. Absence of Cet1's NTD decreases FACT targeting to ADH1 and consequently reduces the engagement of Pol II in transcriptional elongation, leading to promoter-proximal accumulation of Pol II. Similar results were also observed at other genes. Consistently, Cet1 interacts with FACT. Collectively, our results support the notion that Cet1's NTD promotes FACT targeting to the active gene independently of mRNA-capping activity in facilitating Pol II's engagement in transcriptional elongation, thus deciphering a novel regulatory pathway of gene expression.


Assuntos
Hidrolases Anidrido Ácido/metabolismo , Álcool Desidrogenase/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Grupo de Alta Mobilidade/metabolismo , RNA Polimerase II/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Elongação da Transcrição Genética , Fatores de Elongação da Transcrição/metabolismo , Hidrolases Anidrido Ácido/genética , Álcool Desidrogenase/genética , Sítios de Ligação , Cromatina/genética , Proteínas de Ligação a DNA/genética , Proteínas de Grupo de Alta Mobilidade/genética , Regiões Promotoras Genéticas , RNA Polimerase II/genética , RNA Mensageiro , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Elongação da Transcrição/genética
20.
Mol Cell Biol ; 36(11): 1691-703, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27044865

RESUMO

FACT (facilitates chromatin transcription), an evolutionarily conserved histone chaperone involved in transcription and other DNA transactions, is upregulated in cancers, and its downregulation is associated with cellular death. However, it is not clearly understood how FACT is fine-tuned for normal cellular functions. Here, we show that the FACT subunit Spt16 is ubiquitylated by San1 (an E3 ubiquitin ligase) and degraded by the 26S proteasome. Enhanced abundance of Spt16 in the absence of San1 impairs transcriptional elongation. Likewise, decreased abundance of Spt16 also reduces transcription. Thus, an optimal level of Spt16 is required for efficient transcriptional elongation, which is maintained by San1 via ubiquitylation and proteasomal degradation. Consistently, San1 associates with the coding sequences of active genes to regulate Spt16's abundance. Further, we found that enhanced abundance of Spt16 in the absence of San1 impairs chromatin reassembly at the coding sequence, similarly to the results seen following inactivation of Spt16. Efficient chromatin reassembly enhances the fidelity of transcriptional elongation. Taken together, our results demonstrate for the first time a fine-tuning of FACT by a ubiquitin proteasome system in promoting chromatin reassembly in the wake of elongating RNA polymerase II and transcriptional elongation, thus revealing novel regulatory mechanisms of gene expression.


Assuntos
Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Fatores de Elongação da Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Montagem e Desmontagem da Cromatina , Regulação Fúngica da Expressão Gênica , RNA Fúngico/metabolismo , Saccharomyces cerevisiae/metabolismo , Elongação da Transcrição Genética , Ubiquitinação
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