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Adar null mutant mouse embryos die with aberrant double-stranded RNA (dsRNA)-driven interferon induction, and Adar Mavs double mutants, in which interferon induction is prevented, die soon after birth. Protein kinase R (Pkr) is aberrantly activated in Adar Mavs mouse pup intestines before death, intestinal crypt cells die, and intestinal villi are lost. Adar Mavs Eifak2 (Pkr) triple mutant mice rescue all defects and have long-term survival. Adenosine deaminase acting on RNA 1 (ADAR1) and PKR co-immunoprecipitate from cells, suggesting PKR inhibition by direct interaction. AlphaFold studies on an inhibitory PKR dsRNA binding domain (dsRBD)-kinase domain interaction before dsRNA binding and on an inhibitory ADAR1 dsRBD3-PKR kinase domain interaction on dsRNA provide a testable model of the inhibition. Wild-type or editing-inactive human ADAR1 expressed in A549 cells inhibits activation of endogenous PKR. ADAR1 dsRNA binding is required for, but is not sufficient for, PKR inhibition. Mutating the ADAR1 dsRBD3-PKR contact prevents co-immunoprecipitation, ADAR1 inhibition of PKR activity, and co-localization of ADAR1 and PKR in cells.
Assuntos
Adenosina Desaminase , RNA de Cadeia Dupla , Proteínas de Ligação a RNA , eIF-2 Quinase , Adenosina Desaminase/metabolismo , Adenosina Desaminase/genética , eIF-2 Quinase/metabolismo , RNA de Cadeia Dupla/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Humanos , Animais , Camundongos , Ligação Proteica , Ativação Enzimática , Células A549 , Domínios ProteicosRESUMO
Communication between the maternal endometrium and developing embryo/conceptus is critical to support successful pregnancy to term. Studying the peri-implantation period of pregnancy is critical as this is when most pregnancy loss occurs in cattle. Our current understanding of these interactions is limited, due to the lack of appropriate in vitro models to assess these interactions. The endometrium is a complex and heterogeneous tissue that is regulated in a transcriptional and translational manner throughout the oestrous cycle. While there are in vitro models to study endometrial function, they are static and 2D in nature or explant models and are limited in how well they recapitulate the in vivo endometrium. Recent developments in organoid systems, microfluidic approaches, extracellular matrix biology, and in silico approaches provide a new opportunity to develop in vitro systems that better model the in vivo scenario. This will allow us to investigate in a more high-throughput manner the fundamental molecular interactions that are required for successful pregnancy in cattle.
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Implantação do Embrião , Endométrio , Gravidez , Feminino , Bovinos , Animais , Embrião de MamíferosRESUMO
ConspectusThe adenosine deaminase acting on RNA (ADAR) enzymes that catalyze the conversion of adenosine to inosine in double-stranded (ds)RNA are evolutionarily conserved and are essential for many biological functions including nervous system function, hematopoiesis, and innate immunity. Initially it was assumed that the wide-ranging biological roles of ADARs are due to inosine in mRNA being read as guanosine by the translational machinery, allowing incomplete RNA editing in a target codon to generate two different proteins from the same primary transcript. In humans, there are approximately seventy-six positions that undergo site-specific editing in tissues at greater than 20% efficiency that result in recoding. Many of these transcripts are expressed in the central nervous system (CNS) and edited by ADAR2. Exploiting mouse genetic models revealed that transgenic mice lacking the gene encoding Adar2 die within 3 weeks of birth. Therefore, the role of ADAR2 in generating protein diversity in the nervous system is clear, but why is ADAR RNA editing activity essential in other biological processes, particularly editing mainly involving ADAR1? ADAR1 edits human transcripts having embedded Alu element inverted repeats (AluIRs), but the link from this activity to innate immunity activation was elusive. Mice lacking the gene encoding Adar1 are embryonically lethal, and a major breakthrough was the discovery that the role of Adar1 in innate immunity is due to its ability to edit such repetitive element inverted repeats which have the ability to form dsRNA in transcripts. The presence of inosine prevents activation of the dsRNA sensor melanoma differentiation-associated protein 5 (Mda5). Thus, inosine helps the cell discriminate self from non-self RNA, acting like a barcode on mRNA. As innate immunity is key to many different biological processes, the basis for this widespread biological role of the ADAR1 enzyme became evident.Our group has been studying ADARs from the outset of research on these enzymes. In this Account, we give a historical perspective, moving from the initial purification of ADAR1 and ADAR2 and cloning of their encoding genes up to the current research focus in the field and what questions still remain to be addressed. We discuss the characterizations of the proteins, their localizations, posttranslational modifications, and dimerization, and how all of these affect their biological activities. Another aspect we explore is the use of mouse and Drosophila genetic models to study ADAR functions and how these were crucial in determining the biological functions of the ADAR proteins. Finally, we describe the severe consequences of rare mutations found in the human genes encoding ADAR1 and ADAR2.
Assuntos
Adenosina Desaminase , RNA de Cadeia Dupla , Animais , Camundongos , Humanos , Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , RNA de Cadeia Dupla/genética , Imunidade Inata , RNA Mensageiro/genética , Inosina/genética , Inosina/metabolismoRESUMO
PURPOSE: Although improvements in breast cancer detection and treatment have significantly increased survival, important questions related to breast cancer risk, prognosis, and survivorship remain. This brief report describes the Health of Women (HOW) Study® methodology and characterizes the participants who completed the My Health Overview and My Breast Cancer modules. METHODS: The HOW Study® was a collection of cross-sectional, web-based modules designed to survey a large number of participants with and without breast cancer. RESULTS: A total of 42,540 participants completed the My Health Overview module, of whom 13,285 (31.2%) reported a history of breast cancer. The majority of participants were white (94.3%), female (99.5%), married (74.1%), college educated (73.2%), post-menopausal (91.1%), parous (68.8%), and reported breastfeeding their children (56.0%). A total of 11,670 participants reported a history of breast cancer in the My Breast Cancer module. The majority of survivors reported on their primary breast cancer and were diagnosed over the age of 40 years (83.5%), had either Stage I or Stage II breast cancer (63.1%), and were treated with surgery (98.8%), radiation (64.8%), and/or chemotherapy (62.3%). CONCLUSIONS: The HOW Study® provides an innovative framework for collecting large amounts of epidemiological data in an efficient and minimally invasive way. Data are publicly available to researchers upon request. IMPLICATIONS FOR CANCER SURVIVORS: The HOW Study® can be leveraged to answer important questions about survivorship, and researchers are encouraged to utilize this new data source.
Assuntos
Neoplasias da Mama , Sobreviventes de Câncer , Adulto , Feminino , Humanos , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/terapia , Estudos Transversais , Internet , Qualidade de Vida , Fatores de RiscoRESUMO
The COVID-19 pandemic influenced health care with effects on contraception access emerging. The study objectives were to analyze pandemic impacts on birth control (BC) use and access; and evaluate perceptions of pharmacist-prescribed BC. A 50-item survey was distributed by 31 Michigan community pharmacies to women aged 18-45 over a three-month period. The survey link was also posted on two websites. 147 surveys were analyzed. Respondents were 29 ± 7.9 years old, primarily white (77%) and straight (81%). Fifty-eight percent of respondents used prescription BC, mostly to prevent pregnancy (84%) with oral pills (76%) being the most common formulation. Some BC users (25%) were worried about BC access and 27% had difficulty taking BC regularly. Half of the respondents (50%) would likely use pharmacist-prescribed BC if available, with advantages being more convenient than visiting a doctor's office (71%) and easier access (69%). The major concern about pharmacist-prescribed BC was women not receiving PAP smears and screenings (61%). Respondents reported high confidence (72%) in pharmacist-prescribed BC and believe it would help prevent unintended pregnancies (69%). Some respondents experienced altered BC use and access. Half of the respondents supported pharmacist-prescribed BC. Pharmacist-prescribed BC could help solve pandemic-related access problems.
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The adenosine deaminase acting on RNA (ADAR) enzymes are essential for neuronal function and innate immune control. ADAR1 RNA editing prevents aberrant activation of antiviral dsRNA sensors through editing of long, double-stranded RNAs (dsRNAs). In this review, we focus on the ADAR2 proteins involved in the efficient, highly site-specific RNA editing to recode open reading frames first discovered in the GRIA2 transcript encoding the key GLUA2 subunit of AMPA receptors; ADAR1 proteins also edit many of these sites. We summarize the history of ADAR2 protein research and give an up-to-date review of ADAR2 structural studies, human ADARBI (ADAR2) mutants causing severe infant seizures, and mouse disease models. Structural studies on ADARs and their RNA substrates facilitate current efforts to develop ADAR RNA editing gene therapy to edit disease-causing single nucleotide polymorphisms (SNPs). Artificial ADAR guide RNAs are being developed to retarget ADAR RNA editing to new target transcripts in order to correct SNP mutations in them at the RNA level. Site-specific RNA editing has been expanded to recode hundreds of sites in CNS transcripts in Drosophila and cephalopods. In Drosophila and C. elegans, ADAR RNA editing also suppresses responses to self dsRNA.
Assuntos
Adenosina Desaminase , Adenosina Desaminase/metabolismo , Animais , Antivirais , Caenorhabditis elegans/genética , Drosophila/genética , Terapia Genética , Humanos , Camundongos , RNA de Cadeia Dupla/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Receptores de AMPA/genética , Receptores de AMPA/metabolismoRESUMO
BACKGROUND: Morbidity and mortality associated with preventable diseases can be reduced with the use of preventive health services. We evaluated the uptake and retention of preventive health behaviors and management of accidental medication poisonings in older adults after a health prevention educational component was combined with a brown bag medication review. METHODS: This study used a cohort design and was conducted in six urban senior centers and three independent senior living communities in Detroit, Michigan. Participants included 85 older adults (>60 years old) taking five or more medications with 63 participants returning follow up materials. Pharmacy personnel conducted brown bag medication reviews that were combined with a preventive health education component. Information was collected on medications, vaccinations, supplement use, and accidental medication poisoning management. Participants were given written recommendations on prescription medications and preventive health therapies to improve health and medication use. An investigator developed program satisfaction survey was administered immediately after the review. An investigator-developed follow-up preventive health implementation survey was conducted at least 3 months later to assess recommendation implementation. RESULTS: Participants' mean age was 75.9 ± 8.5 years. Fifty-six older adults had 124 recommendations in preventive health in total (1-5/participant). Eleven participants had no recommendations. Sixty-three participants (74%) returned follow-up preventive health surveys. Twenty-three percent of recommendations were already implemented with 34% planned to be done in the future. Poisoning management knowledge increased for 13 participants, reporting they would call the poison control center. The program was well received, with participants reporting high satisfaction scores (4.8 ± 0.7 out of 5). CONCLUSIONS: Brown bag medication reviews can be an effective method to promote the uptake of preventive health behaviors among older adults, but additional accidental medication poisoning management education is still needed.
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Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Revisão de Medicamentos , Humanos , Idoso , Idoso de 80 Anos ou mais , Polimedicação , Centros de Controle de Intoxicações , Serviços Preventivos de SaúdeRESUMO
It is estimated that behaviors such as poor diet, alcohol consumption, tobacco use, sedentary behavior, and excessive ultraviolet exposure account for nearly one-half of all cancer morbidity and mortality. Accordingly, the behavioral, social, and communication sciences have been important contributors to cancer prevention and control research, with methodological advances and implementation science helping to produce optimally effective interventions. To sustain these contributions, it is vital to adapt to the contemporary context. Efforts must consider ancillary effects of the 2019 coronavirus disease pandemic, profound changes in the information environment and public understanding of and trust in science, renewed attention to structural racism and social determinants of health, and the rapidly increasing population of cancer survivors. Within this context, it is essential to accelerate reductions in tobacco use across all population subgroups; consider new models of energy balance (diet, physical activity, sedentary behavior); increase awareness of alcohol as a risk factor for cancer; and identify better communication practices in the context of cancer-related decisions such as screening and genetic testing. Successful integration of behavioral research and cancer prevention depends on working globally and seamlessly across disciplines, taking a multilevel approach where possible. Methodological and analytic approaches should be emphasized in research training programs and should use new and underused data sources and technologies. As the leadership core of the National Cancer Institute's Behavioral Research Program, we reflect on these challenges and opportunities and consider implications for the next phase of behavioral research in cancer prevention and control.
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Pesquisa Comportamental , Neoplasias , Consumo de Bebidas Alcoólicas/efeitos adversos , Consumo de Bebidas Alcoólicas/epidemiologia , Atenção à Saúde , Dieta , Exercício Físico , Humanos , Neoplasias/epidemiologia , Neoplasias/prevenção & controleRESUMO
ADAR1 edits adenosines to inosines in cellular double-stranded (ds)RNA, thereby preventing aberrant activation of antiviral dsRNA sensors, as well as interferon (IFN) induction in Aicardi-Goutières syndrome (AGS) encephalopathy. Recently, Nakahama et al., Tang et al., Maurano et al., and de Reuver et al. demonstrated that Adar1 Zα domain-mutant mice show aberrant MDA5 and PKR activation, developing encephalopathies; short Z-RNA patches within cellular dsRNA are unexpectedly crucial in causing aberrant antiviral responses.
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Adenosina Desaminase , Doenças Autoimunes do Sistema Nervoso , Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Animais , Antivirais , Doenças Autoimunes do Sistema Nervoso/genética , Humanos , Camundongos , Edição de RNA , RNA de Cadeia DuplaRESUMO
The expression of long noncoding RNAs is highly enriched in the human nervous system. However, the function of neuronal lncRNAs in the cytoplasm and their potential translation remains poorly understood. Here we performed Poly-Ribo-Seq to understand the interaction of lncRNAs with the translation machinery and the functional consequences during neuronal differentiation of human SH-SY5Y cells. We discovered 237 cytoplasmic lncRNAs up-regulated during early neuronal differentiation, 58%-70% of which are associated with polysome translation complexes. Among these polysome-associated lncRNAs, we find 45 small ORFs to be actively translated, 17 specifically upon differentiation. Fifteen of 45 of the translated lncRNA-smORFs exhibit sequence conservation within Hominidea, suggesting they are under strong selective constraint in this clade. The profiling of publicly available data sets revealed that 8/45 of the translated lncRNAs are dynamically expressed during human brain development, and 22/45 are associated with cancers of the central nervous system. One translated lncRNA we discovered is LINC01116, which is induced upon differentiation and contains an 87 codon smORF exhibiting increased ribosome profiling signal upon differentiation. The resulting LINC01116 peptide localizes to neurites. Knockdown of LINC01116 results in a significant reduction of neurite length in differentiated cells, indicating it contributes to neuronal differentiation. Our findings indicate cytoplasmic lncRNAs interact with translation complexes, are a noncanonical source of novel peptides, and contribute to neuronal function and disease. Specifically, we demonstrate a novel functional role for LINC01116 during human neuronal differentiation.
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Diferenciação Celular/genética , Neurônios/metabolismo , Polirribossomos/genética , Biossíntese de Proteínas , RNA Longo não Codificante/genética , Sequência de Bases , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Encéfalo/patologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Citoplasma/genética , Citoplasma/metabolismo , Humanos , Neurônios/citologia , Fases de Leitura Aberta , Polirribossomos/metabolismo , RNA Longo não Codificante/classificação , RNA Longo não Codificante/metabolismo , Análise de Sequência de RNA , Tretinoína/farmacologiaRESUMO
Modified bases act as marks on cellular RNAs so that they can be distinguished from foreign RNAs, reducing innate immune responses to endogenous RNA. In humans, mutations giving reduced levels of one base modification, adenosine-to-inosine deamination, cause a viral infection mimic syndrome, a congenital encephalitis with aberrant interferon induction. These Aicardi-Goutières syndrome 6 mutations affect adenosine deaminase acting on RNA 1 (ADAR1), which generates inosines in endogenous double-stranded (ds)RNA. The inosine base alters dsRNA structure to prevent aberrant activation of antiviral cytosolic helicase RIG-I-like receptors. We review how effects of inosines, ADARs, and other modified bases have been shown to be important in innate immunity and cancer.
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Imunidade Inata , Edição de RNA , Proteínas de Ligação a RNA , Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Humanos , RNA de Cadeia Dupla , Proteínas de Ligação a RNA/metabolismo , TranscriptomaRESUMO
RNA editing is one of the most prevalent and abundant forms of post-transcriptional RNA modification observed in normal physiological processes and often aberrant in diseases including cancer. RNA editing changes the sequences of mRNAs, making them different from the source DNA sequence. Edited mRNAs can produce editing-recoded protein isoforms that are functionally different from the corresponding genome-encoded protein isoforms. The major type of RNA editing in mammals occurs by enzymatic deamination of adenosine to inosine (A-to-I) within double-stranded RNAs (dsRNAs) or hairpins in pre-mRNA transcripts. Enzymes that catalyse these processes belong to the adenosine deaminase acting on RNA (ADAR) family. The vast majority of knowledge on the RNA editing landscape relevant to human disease has been acquired using in vitro cancer cell culture models. The limitation of such in vitro models, however, is that the physiological or disease relevance of results obtained is not necessarily obvious. In this review we focus on discussing in vivo occurring RNA editing events that have been identified in human cancer tissue using samples surgically resected or clinically retrieved from patients. We discuss how RNA editing events occurring in tumours in vivo can identify pathological signalling mechanisms relevant to human cancer physiology which is linked to the different stages of cancer progression including initiation, promotion, survival, proliferation, immune escape and metastasis.
Assuntos
Adenosina/genética , Carcinogênese/patologia , Inosina/genética , Neoplasias/patologia , Edição de RNA , RNA de Cadeia Dupla/genética , Proteínas de Ligação a RNA/metabolismo , Animais , Carcinogênese/genética , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Proteínas de Ligação a RNA/genéticaRESUMO
BACKGROUND: Adenosine-to-inosine RNA editing is a co-transcriptional/post-transcriptional modification of double-stranded RNA, catalysed by one of two active adenosine deaminases acting on RNA (ADARs), ADAR1 and ADAR2. ADARB1 encodes the enzyme ADAR2 that is highly expressed in the brain and essential to modulate the function of glutamate and serotonin receptors. Impaired ADAR2 editing causes early onset progressive epilepsy and premature death in mice. In humans, ADAR2 dysfunction has been very recently linked to a neurodevelopmental disorder with microcephaly and epilepsy in four unrelated subjects. METHODS: We studied three children from two consanguineous families with severe developmental and epileptic encephalopathy (DEE) through detailed physical and instrumental examinations. Exome sequencing (ES) was used to identify ADARB1 mutations as the underlying genetic cause and in vitro assays with transiently transfected cells were performed to ascertain the impact on ADAR2 enzymatic activity and splicing. RESULTS: All patients showed global developmental delay, intractable early infantile-onset seizures, microcephaly, severe-to-profound intellectual disability, axial hypotonia and progressive appendicular spasticity. ES revealed the novel missense c.1889G>A, p.(Arg630Gln) and deletion c.1245_1247+1 del, p.(Leu415PhefsTer14) variants in ADARB1 (NM_015833.4). The p.(Leu415PhefsTer14) variant leads to incorrect splicing resulting in frameshift with a premature stop codon and loss of enzyme function. In vitro RNA editing assays showed that the p.(Arg630Gln) variant resulted in a severe impairment of ADAR2 enzymatic activity. CONCLUSION: In conclusion, these data support the pathogenic role of biallelic ADARB1 variants as the cause of a distinctive form of DEE, reinforcing the importance of RNA editing in brain function and development.
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Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Encefalopatias/genética , Epilepsia/genética , Transtornos do Neurodesenvolvimento/genética , RNA de Cadeia Dupla/metabolismo , Proteínas de Ligação a RNA/genética , Alelos , Encefalopatias/enzimologia , Encefalopatias/metabolismo , Criança , Pré-Escolar , Consanguinidade , Epilepsia/enzimologia , Feminino , Células HEK293 , Humanos , Mutação , Transtornos do Neurodesenvolvimento/enzimologia , Linhagem , Edição de RNA , Proteínas de Ligação a RNA/metabolismoRESUMO
During the preimplantation period of pregnancy in eutherian mammals, transcriptional and proteomic changes in the uterine endometrium are required to facilitate receptivity to an implanting blastocyst. These changes are mediated, in part, by proteins produced by the developing conceptus (inner cell mass and extraembryonic membranes). We hypothesized that this common process in early pregnancy in eutheria may be facilitated by highly conserved conceptus-derived proteins such as macrophage capping protein (CAPG). We propose that CAPG may share functionality in modifying the transcriptome of the endometrial epithelial cells to facilitate receptivity to implantation in species with different implantation strategies. A recombinant bovine form of CAPG (91% sequence identity between bovine and human) was produced and bovine endometrial epithelial (bEECs) and stromal (bESCs) and human endometrial epithelial cells (hEECs) were cultured for 24 hours with and without recombinant bovine CAPG (rbCAPG). RNA sequencing and quantitative real-time PCR analysis were used to assess the transcriptional response to rbCAPG (Control, vehicle, CAPG 10, 100, 1000 ng/mL: n = 3 biological replicates per treatment per species). Treatment of bEECs with CAPG resulted in alterations in the abundance of 1052 transcripts (629 increased and 423 decreased) compared to vehicle controls. Treatment of hEECs with bovine CAPG increased expression of transcripts previously known to interact with CAPG in different systems (CAPZB, CAPZA2, ADD1, and ADK) compared with vehicle controls (P < .05). In conclusion, we have demonstrated that CAPG, a highly conserved protein in eutherian mammals, elicits a transcriptional response in the endometrial epithelium in species with different implantation strategies that may contribute to pregnancy success.
Assuntos
Comunicação Celular/fisiologia , Implantação do Embrião/fisiologia , Embrião de Mamíferos/metabolismo , Endométrio/metabolismo , Proteínas dos Microfilamentos/metabolismo , Proteínas Nucleares/metabolismo , Útero/metabolismo , Animais , Blastocisto/metabolismo , Blastocisto/fisiologia , Bovinos , Células Cultivadas , Embrião de Mamíferos/fisiologia , Endométrio/fisiologia , Células Epiteliais/metabolismo , Células Epiteliais/fisiologia , Epitélio/metabolismo , Epitélio/fisiologia , Feminino , Humanos , Gravidez , Proteômica/métodos , Transcrição Gênica/fisiologia , Transcriptoma/fisiologia , Útero/fisiologiaRESUMO
ADAR RNA editing enzymes are high-affinity dsRNA-binding proteins that deaminate adenosines to inosines in pre-mRNA hairpins and also exert editing-independent effects. We generated a Drosophila AdarE374A mutant strain encoding a catalytically inactive Adar with CRISPR/Cas9. We demonstrate that Adar adenosine deamination activity is necessary for normal locomotion and prevents age-dependent neurodegeneration. The catalytically inactive protein, when expressed at a higher than physiological level, can rescue neurodegeneration in Adar mutants, suggesting also editing-independent effects. Furthermore, loss of Adar RNA editing activity leads to innate immune induction, indicating that Drosophila Adar, despite being the homolog of mammalian ADAR2, also has functions similar to mammalian ADAR1. The innate immune induction in fly Adar mutants is suppressed by silencing of Dicer-2, which has a RNA helicase domain similar to MDA5 that senses unedited dsRNAs in mammalian Adar1 mutants. Our work demonstrates that the single Adar enzyme in Drosophila unexpectedly has dual functions.
Assuntos
Adenosina Desaminase/genética , Encéfalo/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/imunologia , Imunidade Inata/genética , Edição de RNA/genética , Adenosina Desaminase/química , Monofosfato de Adenosina/metabolismo , Envelhecimento/patologia , Animais , Catálise , Proteínas de Drosophila/química , Proteínas de Drosophila/metabolismo , Regulação da Expressão Gênica , Locomoção , Degeneração Neural/patologia , Mutação Puntual/genética , Domínios Proteicos , RNA Helicases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ribonuclease III/metabolismoRESUMO
The RNA editing enzyme ADAR2 is essential for the recoding of brain transcripts. Impaired ADAR2 editing leads to early-onset epilepsy and premature death in a mouse model. Here, we report bi-allelic variants in ADARB1, the gene encoding ADAR2, in four unrelated individuals with microcephaly, intellectual disability, and epilepsy. In one individual, a homozygous variant in one of the double-stranded RNA-binding domains (dsRBDs) was identified. In the others, variants were situated in or around the deaminase domain. To evaluate the effects of these variants on ADAR2 enzymatic activity, we performed in vitro assays with recombinant proteins in HEK293T cells and ex vivo assays with fibroblasts derived from one of the individuals. We demonstrate that these ADAR2 variants lead to reduced editing activity on a known ADAR2 substrate. We also demonstrate that one variant leads to changes in splicing of ADARB1 transcript isoforms. These findings reinforce the importance of RNA editing in brain development and introduce ADARB1 as a genetic etiology in individuals with intellectual disability, microcephaly, and epilepsy.
Assuntos
Adenosina Desaminase/genética , Predisposição Genética para Doença/genética , Variação Genética/genética , Deficiência Intelectual/genética , Microcefalia/genética , Proteínas de Ligação a RNA/genética , Convulsões/genética , Alelos , Processamento Alternativo/genética , Criança , Pré-Escolar , Células HEK293 , Humanos , Masculino , Splicing de RNA/genéticaRESUMO
BACKGROUND: In fly brains, the Drosophila Adar (adenosine deaminase acting on RNA) enzyme edits hundreds of transcripts to generate edited isoforms of encoded proteins. Nearly all editing events are absent or less efficient in larvae but increase at metamorphosis; the larger number and higher levels of editing suggest editing is most required when the brain is most complex. This idea is consistent with the fact that Adar mutations affect the adult brain most dramatically. However, it is unknown whether Drosophila Adar RNA editing events mediate some coherent physiological effect. To address this question, we performed a genetic screen for suppressors of Adar mutant defects. Adar5G1 null mutant flies are partially viable, severely locomotion defective, aberrantly accumulate axonal neurotransmitter pre-synaptic vesicles and associated proteins, and develop an age-dependent vacuolar brain neurodegeneration. RESULTS: A genetic screen revealed suppression of all Adar5G1 mutant phenotypes tested by reduced dosage of the Tor gene, which encodes a pro-growth kinase that increases translation and reduces autophagy in well-fed conditions. Suppression of Adar5G1 phenotypes by reduced Tor is due to increased autophagy; overexpression of Atg5, which increases canonical autophagy initiation, reduces aberrant accumulation of synaptic vesicle proteins and suppresses all Adar mutant phenotypes tested. Endosomal microautophagy (eMI) is another Tor-inhibited autophagy pathway involved in synaptic homeostasis in Drosophila. Increased expression of the key eMI protein Hsc70-4 also reduces aberrant accumulation of synaptic vesicle proteins and suppresses all Adar5G1 mutant phenotypes tested. CONCLUSIONS: These findings link Drosophila Adar mutant synaptic and neurotransmission defects to more general cellular defects in autophagy; presumably, edited isoforms of CNS proteins are required for optimum synaptic response capabilities in the brain during the behaviorally complex adult life stage.
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Adenosina Desaminase/genética , Autofagia , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Transmissão Sináptica/genética , Adenosina Desaminase/metabolismo , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , MutaçãoRESUMO
Amelogenesis imperfecta (AI) is a heterogeneous group of genetic diseases characterised by dental enamel malformation. Pathogenic variants in at least 33 genes cause syndromic or non-syndromic AI. Recently variants in RELT, encoding an orphan receptor in the tumour necrosis factor (TNF) superfamily, were found to cause recessive AI, as part of a syndrome encompassing small stature and severe childhood infections. Here we describe four additional families with autosomal recessive hypomineralised AI due to previously unreported homozygous mutations in RELT. Three families carried a homozygous missense variant in the fourth exon (c.164C>T, p.(T55I)) and a fourth family carried a homozygous missense variant in the 11th exon (c.1264C>T, p.(R422W)). We found no evidence of additional syndromic symptoms in affected individuals. Analyses of tooth microstructure with computerised tomography and scanning electron microscopy suggest a role for RELT in ameloblasts' coordination and interaction with the enamel matrix. Microsatellite genotyping in families segregating the T55I variant reveals a shared founder haplotype. These findings extend the RELT pathogenic variant spectrum, reveal a founder mutation in the UK Pakistani population and provide detailed analysis of human teeth affected by this hypomineralised phenotype, but do not support a possible syndromic presentation in all those with RELT-variant associated AI.
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Amelogênese Imperfeita/genética , Predisposição Genética para Doença , Receptores do Fator de Necrose Tumoral/genética , Desmineralização do Dente/genética , Amelogênese Imperfeita/diagnóstico por imagem , Amelogênese Imperfeita/patologia , Éxons , Feminino , Homozigoto , Humanos , Masculino , Mutação de Sentido Incorreto/genética , Linhagem , Fenótipo , Desmineralização do Dente/diagnóstico por imagem , Desmineralização do Dente/patologia , Fator de Necrose Tumoral alfa/genéticaRESUMO
The demographic profile of the biomedical workforce in the U.S. does not reflect the population at large, raising concerns that there will be insufficient trained researchers in the future, and the scope of research interests will not be sufficiently broad. To diversify and expand the pool of researchers trained to conduct research on cancer and cancer health disparities, a series of training activities to recruit and train primarily Hispanic students at both the undergraduate and graduate level were developed. The strengths of both a Hispanic Serving Institution and an NIH-designated Comprehensive Cancer Center were leveraged to develop appropriate research training and professional development activities. The career progression of the participants and degree completion rates was tracked, along with persistent interest in biomedical research in general and cancer and cancer health disparities research in particular for these underrepresented individuals. Finally, this report demonstrates that these training activities increased general knowledge about cancer among participants.
Assuntos
Pesquisa Biomédica , Escolha da Profissão , Grupos Minoritários , Prática Associada , Pesquisa Biomédica/educação , Estudos Transversais , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Grupos Minoritários/educação , Recursos HumanosRESUMO
Cetaceans are a clade of highly specialized aquatic mammals that include the largest animals that have ever lived. The largest whales can have â¼1,000× more cells than a human, with long lifespans, leaving them theoretically susceptible to cancer. However, large-bodied and long-lived animals do not suffer higher risks of cancer mortality than humans-an observation known as Peto's Paradox. To investigate the genomic bases of gigantism and other cetacean adaptations, we generated a de novo genome assembly for the humpback whale (Megaptera novaeangliae) and incorporated the genomes of ten cetacean species in a comparative analysis. We found further evidence that rorquals (family Balaenopteridae) radiated during the Miocene or earlier, and inferred that perturbations in abundance and/or the interocean connectivity of North Atlantic humpback whale populations likely occurred throughout the Pleistocene. Our comparative genomic results suggest that the evolution of cetacean gigantism was accompanied by strong selection on pathways that are directly linked to cancer. Large segmental duplications in whale genomes contained genes controlling the apoptotic pathway, and genes inferred to be under accelerated evolution and positive selection in cetaceans were enriched for biological processes such as cell cycle checkpoint, cell signaling, and proliferation. We also inferred positive selection on genes controlling the mammalian appendicular and cranial skeletal elements in the cetacean lineage, which are relevant to extensive anatomical changes during cetacean evolution. Genomic analyses shed light on the molecular mechanisms underlying cetacean traits, including gigantism, and will contribute to the development of future targets for human cancer therapies.