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1.
Sci Rep ; 14(1): 8715, 2024 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622248

RESUMO

Metataxonomic studies of ecosystem microbiotas require the simultaneous processing of samples with contrasting physical and biochemical traits. However, there are no published studies of comparisons of different DNA extraction kits to characterize the microbiotas of the main components of terrestrial ecosystems. Here, and to our knowledge for the first time, five DNA extraction kits were used to investigate the composition and diversity of the microbiota of a subset of samples typically studied in terrestrial ecosystems such as bulk soil, rhizosphere soil, invertebrate taxa and mammalian feces. DNA extraction kit was associated with changes in the relative abundance of hundreds of ASVs, in the same samples, resulting in significant differences in alpha and beta diversity estimates of their microbiotas. Importantly, the impact of DNA extraction kit on sample diversity varies according to sample type, with mammalian feces and soil samples showing the most and least consistent diversity estimates across DNA extraction kits, respectively. We show that the MACHEREY-NAGEL NucleoSpin® Soil kit was associated with the highest alpha diversity estimates, providing the highest contribution to the overall sample diversity, as indicated by comparisons with computationally assembled reference communities, and is recommended to be used for any large-scale microbiota study of terrestrial ecosystems.


Assuntos
Ecossistema , Microbiota , Animais , DNA Bacteriano/genética , DNA/genética , Fezes , Solo , RNA Ribossômico 16S/genética , Mamíferos/genética
2.
Proc Natl Acad Sci U S A ; 121(17): e2316646121, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38625943

RESUMO

Circadian regulation and temperature dependency are important orchestrators of molecular pathways. How the integration between these two drivers is achieved, is not understood. We monitored circadian- and temperature-dependent effects on transcription dynamics of cold-response protein RNA Binding Motif 3 (Rbm3). Temperature changes in the mammalian master circadian pacemaker, the suprachiasmatic nucleus (SCN), induced Rbm3 transcription and regulated its circadian periodicity, whereas the core clock gene Per2 was unaffected. Rbm3 induction depended on a full Brain And Muscle ARNT-Like Protein 1 (Bmal1) complement: reduced Bmal1 erased Rbm3 responses and weakened SCN circuit resilience to temperature changes. By focusing on circadian and temperature dependency, we highlight weakened transmission between core clock and downstream pathways as a potential route for reduced circadian resilience.


Assuntos
Ritmo Circadiano , Proteínas Circadianas Period , Animais , Ritmo Circadiano/fisiologia , Temperatura , Proteínas Circadianas Period/metabolismo , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/metabolismo , RNA/metabolismo , Núcleo Supraquiasmático/metabolismo , Mamíferos/genética
3.
Nat Commun ; 15(1): 3151, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38605055

RESUMO

Endogenous retroviruses (ERVs) are ancient retroviral remnants integrated in host genomes, and commonly deleted through unequal homologous recombination, leaving solitary long terminal repeats (solo-LTRs). This study, analysing the genomes of 362 bird species and their reptilian and mammalian outgroups, reveals an unusually higher level of solo-LTRs formation in birds, indicating evolutionary forces might have purged ERVs during evolution. Strikingly in the order Passeriformes, and especially the parvorder Passerida, endogenous retrovirus K (ERVK) solo-LTRs showed bursts of formation and recurrent accumulations coinciding with speciation events over past 22 million years. Moreover, our results indicate that the ongoing expansion of ERVK solo-LTRs in these bird species, marked by high transcriptional activity of ERVK retroviral genes in reproductive organs, caused variation of solo-LTRs between individual zebra finches. We experimentally demonstrated that cis-regulatory activity of recently evolved ERVK solo-LTRs may significantly increase the expression level of ITGA2 in the brain of zebra finches compared to chickens. These findings suggest that ERVK solo-LTRs expansion may introduce novel genomic sequences acting as cis-regulatory elements and contribute to adaptive evolution. Overall, our results underscore that the residual sequences of ancient retroviruses could influence the adaptive diversification of species by regulating host gene expression.


Assuntos
Retrovirus Endógenos , Passeriformes , Animais , Retrovirus Endógenos/genética , Passeriformes/genética , Galinhas/genética , Sequências Repetidas Terminais/genética , Recombinação Homóloga , Mamíferos/genética
4.
Elife ; 122024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38577979

RESUMO

Splicing is the stepwise molecular process by which introns are removed from pre-mRNA and exons are joined together to form mature mRNA sequences. The ordering and spatial distribution of these steps remain controversial, with opposing models suggesting splicing occurs either during or after transcription. We used single-molecule RNA FISH, expansion microscopy, and live-cell imaging to reveal the spatiotemporal distribution of nascent transcripts in mammalian cells. At super-resolution levels, we found that pre-mRNA formed clouds around the transcription site. These clouds indicate the existence of a transcription-site-proximal zone through which RNA move more slowly than in the nucleoplasm. Full-length pre-mRNA undergo continuous splicing as they move through this zone following transcription, suggesting a model in which splicing can occur post-transcriptionally but still within the proximity of the transcription site, thus seeming co-transcriptional by most assays. These results may unify conflicting reports of co-transcriptional versus post-transcriptional splicing.


Assuntos
Precursores de RNA , Transcrição Gênica , Animais , Precursores de RNA/genética , Precursores de RNA/metabolismo , Splicing de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA , Íntrons/genética , Mamíferos/genética
5.
BMC Genomics ; 25(1): 344, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38580899

RESUMO

BACKGROUND: Genome-wide DNA demethylation occurs in mammalian primordial germ cells (PGCs) as part of the epigenetic reprogramming important for gametogenesis and resetting the epigenetic information for totipotency. Dppa3 (also known as Stella or Pgc7) is highly expressed in mouse PGCs and oocytes and encodes a factor essential for female fertility. It prevents excessive DNA methylation in oocytes and ensures proper gene expression in preimplantation embryos: however, its role in PGCs is largely unexplored. In the present study, we investigated whether or not DPPA3 has an impact on CG methylation/demethylation in mouse PGCs. RESULTS: We show that DPPA3 plays a role in genome-wide demethylation in PGCs even before sex differentiation. Dppa3 knockout female PGCs show aberrant hypermethylation, most predominantly at H3K9me3-marked retrotransposons, which persists up to the fully-grown oocyte stage. DPPA3 works downstream of PRDM14, a master regulator of epigenetic reprogramming in embryonic stem cells and PGCs, and independently of TET1, an enzyme that hydroxylates 5-methylcytosine. CONCLUSIONS: The results suggest that DPPA3 facilitates DNA demethylation through a replication-coupled passive mechanism in PGCs. Our study identifies DPPA3 as a novel epigenetic reprogramming factor in mouse PGCs.


Assuntos
Proteínas Cromossômicas não Histona , Desmetilação do DNA , Epigênese Genética , Animais , Feminino , Camundongos , Proteínas Cromossômicas não Histona/metabolismo , Metilação de DNA , Genoma , Células Germinativas/metabolismo , Mamíferos/genética
6.
Commun Biol ; 7(1): 394, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561421

RESUMO

Brainbow is a genetic cell-labeling technique that allows random colorization of multiple cells and real-time visualization of cell fate within a tissue, providing valuable insights into understanding complex biological processes. However, fluorescent proteins (FPs) in Brainbow have distinct excitation spectra with peak difference greater than 35 nm, which requires sequential imaging under multiple excitations and thus leads to long acquisition times. In addition, they are not easily used together with other fluorophores due to severe spectral bleed-through. Here, we report the development of a single-wavelength excitable Brainbow, UFObow, incorporating three newly developed blue-excitable FPs. We have demonstrated that UFObow enables not only tracking the growth dynamics of tumor cells in vivo but also mapping spatial distribution of immune cells within a sub-cubic centimeter tissue, revealing cell heterogeneity. This provides a powerful means to explore complex biology in a simultaneous imaging manner at a single-cell resolution in organs or in vivo.


Assuntos
Diagnóstico por Imagem , Técnicas Genéticas , Animais , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Corantes , Mamíferos/genética
7.
BMC Genomics ; 25(1): 323, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561663

RESUMO

BACKGROUND: Cow milk fat is an essential indicator for evaluating and measuring milk quality and cow performance. Growing research has identified the molecular functions of circular RNAs (circRNAs) necessary for mammary gland development and lactation in mammals. METHOD: The present study analyzed circRNA expression profiling data in mammary epithelial cells (MECs) from cows with highly variable milk fat percentage (MFP) using differential expression analysis and weighted gene co-expression network analysis (WGCNA). RESULTS: A total of 309 differentially expressed circRNAs (DE-circRNAs) were identified in the high and low MFP groups. WGCNA analysis revealed that the pink module was significantly associated with MFP (r = - 0.85, P = 0.007). Parental genes of circRNAs in this module were enriched mainly in lipid metabolism-related signaling pathways, such as focal adhesion, ECM-receptor interaction, adherens junction and AMPK. Finally, six DE-circRNAs were screened from the pink module: circ_0010571, circ_0007797, circ_0002746, circ_0003052, circ_0004319, and circ_0012840. Among them, circ_0002746, circ_0003052, circ_0004319, and circ_0012840 had circular structures and were highly expressed in mammary tissues. Subcellular localization revealed that these four DE-circRNAs may play a regulatory role in the mammary glands of dairy cows, mainly as competitive endogenous RNAs (ceRNAs). Seven hub target genes (GNB1, GNG2, PLCB1, PLCG1, ATP6V0C, NDUFS4, and PIGH) were obtained by constructing the regulatory network of their ceRNAs and then analyzed by CytoHubba and MCODE plugins in Cytoscape. Functional enrichment analysis revealed that these genes are crucial and most probable ceRNA regulators in milk fat metabolism. CONCLUSIONS: Our study identified several vital circRNAs and ceRNAs affecting milk fat synthesis, providing new research ideas and a theoretical basis for cow lactation, milk quality, and breed improvement.


Assuntos
MicroRNAs , RNA Circular , Feminino , Bovinos , Animais , RNA Circular/genética , RNA Circular/metabolismo , Leite/metabolismo , 60414 , Lactação/genética , Metabolismo dos Lipídeos/genética , Redes Reguladoras de Genes , MicroRNAs/genética , Mamíferos/genética
8.
Epigenetics ; 19(1): 2337085, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38595049

RESUMO

The PhiC31 integration system allows for targeted and efficient transgene integration and expression by recognizing pseudo attP sites in mammalian cells and integrating the exogenous genes into the open chromatin regions of active chromatin. In order to investigate the regulatory patterns of efficient gene expression in the open chromatin region of PhiC31 integration, this study utilized Ubiquitous Chromatin Opening Element (UCOE) and activating RNA (saRNA) to modulate the chromatin structure in the promoter region of the PhiC31 integration vector. The study analysed the effects of DNA methylation and nucleosome occupancy changes in the integrated promoter on gene expression levels. The results showed that for the OCT4 promoter with moderate CG density, DNA methylation had a smaller impact on expression compared to changes in nucleosome positioning near the transcription start site, which was crucial for enhancing downstream gene expression. On the other hand, for the SOX2 promoter with high CG density, increased methylation in the CpG island upstream of the transcription start site played a key role in affecting high expression, but the positioning and clustering of nucleosomes also had an important influence. In conclusion, analysing the DNA methylation patterns, nucleosome positioning, and quantity distribution of different promoters can determine whether the PhiC31 integration site possesses the potential to further enhance expression or overcome transgene silencing effects by utilizing chromatin regulatory elements.


Assuntos
Cromatina , Nucleossomos , Animais , Cromatina/genética , Nucleossomos/genética , Metilação de DNA , Ilhas de CpG , Regiões Promotoras Genéticas , Mamíferos/genética
9.
Proc Natl Acad Sci U S A ; 121(16): e2316651121, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38588418

RESUMO

Protecting chromosome ends from misrecognition as double-stranded (ds) DNA breaks is fundamental to eukaryotic viability. The protein complex shelterin prevents a DNA damage response at mammalian telomeres. Mammalian shelterin proteins TRF1 and TRF2 and their homologs in yeast and protozoa protect telomeric dsDNA. N-terminal homodimerization and C-terminal Myb-domain-mediated dsDNA binding are two structural hallmarks of end protection by TRF homologs. Yet our understanding of how Caenorhabditis elegans protects its telomeric dsDNA is limited. Recently identified C. elegans proteins TEBP-1 (also called DTN-1) and TEBP-2 (also called DTN-2) are functional homologs of TRF proteins, but how they bind DNA and whether or how they dimerize is not known. TEBP-1 and TEBP-2 harbor three Myb-containing domains (MCDs) and no obvious dimerization domain. We demonstrate biochemically that only the third MCD binds DNA. We solve the X-ray crystal structure of TEBP-2 MCD3 with telomeric dsDNA to reveal the structural mechanism of telomeric dsDNA protection in C. elegans. Mutagenesis of the DNA-binding site of TEBP-1 and TEBP-2 compromises DNA binding in vitro, and increases DNA damage signaling, lengthens telomeres, and decreases brood size in vivo. Via an X-ray crystal structure, biochemical validation of the dimerization interface, and SEC-MALS analysis, we demonstrate that MCD1 and MCD2 form a composite dimerization module that facilitates not only TEBP-1 and TEBP-2 homodimerization but also heterodimerization. These findings provide fundamental insights into C. elegans telomeric dsDNA protection and highlight how different eukaryotes have evolved distinct strategies to solve the chromosome end protection problem.


Assuntos
Proteínas de Caenorhabditis elegans , Proteínas de Ligação a Telômeros , Animais , Proteínas de Ligação a Telômeros/metabolismo , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Dimerização , Proteína 1 de Ligação a Repetições Teloméricas/genética , Proteína 1 de Ligação a Repetições Teloméricas/química , Proteína 1 de Ligação a Repetições Teloméricas/metabolismo , Ligação Proteica , Telômero/genética , Telômero/metabolismo , Complexo Shelterina , DNA/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas , Mamíferos/genética
10.
Nat Commun ; 15(1): 3311, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632224

RESUMO

Inducible gene expression systems can be used to control the expression of a gene of interest by means of a small-molecule. One of the most common designs involves engineering a small-molecule responsive transcription factor (TF) and its cognate promoter, which often results in a compromise between minimal uninduced background expression (leakiness) and maximal induced expression. Here, we focus on an alternative strategy using quantitative synthetic biology to mitigate leakiness while maintaining high expression, without modifying neither the TF nor the promoter. Through mathematical modelling and experimental validations, we design the CASwitch, a mammalian synthetic gene circuit based on combining two well-known network motifs: the Coherent Feed-Forward Loop (CFFL) and the Mutual Inhibition (MI). The CASwitch combines the CRISPR-Cas endoribonuclease CasRx with the state-of-the-art Tet-On3G inducible gene system to achieve high performances. To demonstrate the potentialities of the CASwitch, we apply it to three different scenarios: enhancing a whole-cell biosensor, controlling expression of a toxic gene and inducible production of Adeno-Associated Virus (AAV) vectors.


Assuntos
Regulação da Expressão Gênica , Genes Sintéticos , Animais , Fatores de Transcrição/genética , Redes Reguladoras de Genes , Regiões Promotoras Genéticas , Mamíferos/genética , Sistemas CRISPR-Cas
11.
Elife ; 132024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38639482

RESUMO

Despite rapid evolution across eutherian mammals, the X-linked MIR-506 family miRNAs are located in a region flanked by two highly conserved protein-coding genes (SLITRK2 and FMR1) on the X chromosome. Intriguingly, these miRNAs are predominantly expressed in the testis, suggesting a potential role in spermatogenesis and male fertility. Here, we report that the X-linked MIR-506 family miRNAs were derived from the MER91C DNA transposons. Selective inactivation of individual miRNAs or clusters caused no discernible defects, but simultaneous ablation of five clusters containing 19 members of the MIR-506 family led to reduced male fertility in mice. Despite normal sperm counts, motility, and morphology, the KO sperm were less competitive than wild-type sperm when subjected to a polyandrous mating scheme. Transcriptomic and bioinformatic analyses revealed that these X-linked MIR-506 family miRNAs, in addition to targeting a set of conserved genes, have more targets that are critical for spermatogenesis and embryonic development during evolution. Our data suggest that the MIR-506 family miRNAs function to enhance sperm competitiveness and reproductive fitness of the male by finetuning gene expression during spermatogenesis.


Assuntos
MicroRNAs , Sêmen , Masculino , Animais , Camundongos , Sêmen/metabolismo , Espermatogênese/genética , Espermatozoides/metabolismo , Testículo/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Mamíferos/genética
12.
Proc Natl Acad Sci U S A ; 121(15): e2322563121, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38557192

RESUMO

Mammalian switch/sucrose nonfermentable (mSWI/SNF) ATPase degraders have been shown to be effective in enhancer-driven cancers by functioning to impede oncogenic transcription factor chromatin accessibility. Here, we developed AU-24118, an orally bioavailable proteolysis-targeting chimera (PROTAC) degrader of mSWI/SNF ATPases (SMARCA2 and SMARCA4) and PBRM1. AU-24118 demonstrated tumor regression in a model of castration-resistant prostate cancer (CRPC) which was further enhanced with combination enzalutamide treatment, a standard of care androgen receptor (AR) antagonist used in CRPC patients. Importantly, AU-24118 exhibited favorable pharmacokinetic profiles in preclinical analyses in mice and rats, and further toxicity testing in mice showed a favorable safety profile. As acquired resistance is common with targeted cancer therapeutics, experiments were designed to explore potential mechanisms of resistance that may arise with long-term mSWI/SNF ATPase PROTAC treatment. Prostate cancer cell lines exposed to long-term treatment with high doses of a mSWI/SNF ATPase degrader developed SMARCA4 bromodomain mutations and ABCB1 (ATP binding cassette subfamily B member 1) overexpression as acquired mechanisms of resistance. Intriguingly, while SMARCA4 mutations provided specific resistance to mSWI/SNF degraders, ABCB1 overexpression provided broader resistance to other potent PROTAC degraders targeting bromodomain-containing protein 4 and AR. The ABCB1 inhibitor, zosuquidar, reversed resistance to all three PROTAC degraders tested. Combined, these findings position mSWI/SNF degraders for clinical translation for patients with enhancer-driven cancers and define strategies to overcome resistance mechanisms that may arise.


Assuntos
Adenosina Trifosfatases , Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Ratos , Camundongos , Animais , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Linhagem Celular , Cromatina , Mamíferos/genética , Antagonistas de Receptores de Andrógenos , DNA Helicases/genética , Proteínas Nucleares/genética , Fatores de Transcrição/genética
13.
RNA Biol ; 21(1): 1-23, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38629491

RESUMO

Translation fidelity relies on accurate aminoacylation of transfer RNAs (tRNAs) by aminoacyl-tRNA synthetases (AARSs). AARSs specific for alanine (Ala), leucine (Leu), serine, and pyrrolysine do not recognize the anticodon bases. Single nucleotide anticodon variants in their cognate tRNAs can lead to mistranslation. Human genomes include both rare and more common mistranslating tRNA variants. We investigated three rare human tRNALeu variants that mis-incorporate Leu at phenylalanine or tryptophan codons. Expression of each tRNALeu anticodon variant in neuroblastoma cells caused defects in fluorescent protein production without significantly increased cytotoxicity under normal conditions or in the context of proteasome inhibition. Using tRNA sequencing and mass spectrometry we confirmed that each tRNALeu variant was expressed and generated mistranslation with Leu. To probe the flexibility of the entire genetic code towards Leu mis-incorporation, we created 64 yeast strains to express all possible tRNALeu anticodon variants in a doxycycline-inducible system. While some variants showed mild or no growth defects, many anticodon variants, enriched with G/C at positions 35 and 36, including those replacing Leu for proline, arginine, alanine, or glycine, caused dramatic reductions in growth. Differential phenotypic defects were observed for tRNALeu mutants with synonymous anticodons and for different tRNALeu isoacceptors with the same anticodon. A comparison to tRNAAla anticodon variants demonstrates that Ala mis-incorporation is more tolerable than Leu at nearly every codon. The data show that the nature of the amino acid substitution, the tRNA gene, and the anticodon are each important factors that influence the ability of cells to tolerate mistranslating tRNAs.


Assuntos
Aminoacil-tRNA Sintetases , Saccharomyces cerevisiae , Animais , Humanos , Saccharomyces cerevisiae/genética , Anticódon/genética , Leucina/genética , RNA de Transferência de Leucina/genética , Código Genético , Códon , RNA de Transferência/genética , Aminoacil-tRNA Sintetases/genética , Aminoacil-tRNA Sintetases/metabolismo , Alanina/genética , Mamíferos/genética
14.
Nihon Ronen Igakkai Zasshi ; 61(1): 1-12, 2024.
Artigo em Japonês | MEDLINE | ID: mdl-38583963

RESUMO

The epigenome can adequately regulate the on/off states of genes in response to external environmental factors and stress. In recent years, it has been observed that the epigenome, which is modulated through DNA methylation, histone modifications, and chromatin remodeling, changes with age. Alterations in the epigenome lead to the loss of cell-specific epigenome/identity, which in turn triggers a decline in tissue function. In mammals, postnatal epigenomic variations are not only caused by metabolic diseases, such as diabetes or DNA damage, but also by social stress and infectious diseases. Unlike Genome-Wide Association Studies (GWAS), dynamically changing epigenomes, along with their cellular roles, need to be established as objective biomarkers in conjunction with various biological signals, such as walking speed, brain waves, and clinical data. The biological age/aging clock, determined by methylated DNA, has attracted attention, and calorie restriction not only slows the progression of aging, but also seems to suppress it. However, as indicated by gene expression analysis in aging mice, aging is not a linear model, but is represented by nonlinear dynamic changes. Consequently, the development of experimental models and analytical methods that enhance temporal resolution through time-series analysis, tailored to spatial resolution, such as cell distribution and organ specificity, is progressing. Moreover, in recent years, in addition to anti-aging efforts targeting epigenomic variations, global attention has increasingly focused on research and development aimed at rejuvenating treatments, thus leading to the birth of many biotech companies. Aging Hallmarks such as inflammation, stem cells, metabolism, genomic instability, and autophagy, interact closely with the epigenome. Various postnatal and reversible epigenomic controls of aging, including Yamanaka factors (OKSM and OSK), are now entering a new phase. In the future, the development of aging control using diverse modalities, such as mRNA, artificial peptides, and genome editing, is expected, along with an improved molecular understanding of aging and identification of useful biomarkers.


Assuntos
Epigenoma , Histonas , Animais , Camundongos , Histonas/genética , Histonas/metabolismo , Estudo de Associação Genômica Ampla , Biomarcadores , Envelhecimento/genética , Mamíferos/genética , Mamíferos/metabolismo
15.
PLoS One ; 19(4): e0296127, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38626020

RESUMO

Lyme disease is the most prevalent vector-borne infectious disease in Europe and the USA. Borrelia burgdorferi, as the causative agent of Lyme disease, is transmitted to the mammalian host during the tick blood meal. To adapt to the different encountered environments, Borrelia has adjusted the expression pattern of various, mostly outer surface proteins. The function of most B. burgdorferi outer surface proteins remains unknown. We determined the crystal structure of a previously uncharacterized B. burgdorferi outer surface protein BBK01, known to belong to the paralogous gene family 12 (PFam12) as one of its five members. PFam12 members are shown to be upregulated as the tick starts its blood meal. Structural analysis of BBK01 revealed similarity to the coiled coil domain of structural maintenance of chromosomes (SMC) protein family members, while functional studies indicated that all PFam12 members are non-specific DNA-binding proteins. The residues involved in DNA binding were identified and probed by site-directed mutagenesis. The combination of SMC-like proteins being attached to the outer membrane and exposed to the environment or located in the periplasm, as observed in the case of PFam12 members, and displaying the ability to bind DNA, represents a unique feature previously not observed in bacteria.


Assuntos
Borrelia burgdorferi , Doença de Lyme , Carrapatos , Animais , Borrelia burgdorferi/genética , Borrelia burgdorferi/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Doença de Lyme/microbiologia , Carrapatos/genética , Proteínas de Membrana/metabolismo , DNA/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Mamíferos/genética
16.
Epigenetics Chromatin ; 17(1): 9, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561749

RESUMO

BACKGROUND: CTCF is highly likely to be the ancestor of proteins that contain large clusters of C2H2 zinc finger domains, and its conservation is observed across most bilaterian organisms. In mammals, CTCF is the primary architectural protein involved in organizing chromosome topology and mediating enhancer-promoter interactions over long distances. In Drosophila, CTCF (dCTCF) cooperates with other architectural proteins to establish long-range interactions and chromatin boundaries. CTCFs of various organisms contain an unstructured N-terminal dimerization domain (DD) and clusters comprising eleven zinc-finger domains of the C2H2 type. The Drosophila (dCTCF) and human (hCTCF) CTCFs share sequence homology in only five C2H2 domains that specifically bind to a conserved 15 bp motif. RESULTS: Previously, we demonstrated that CTCFs from different organisms carry unstructured N-terminal dimerization domains (DDs) that lack sequence homology. Here we used the CTCFattP(mCh) platform to introduce desired changes in the Drosophila CTCF gene and generated a series of transgenic lines expressing dCTCF with different variants of the N-terminal domain. Our findings revealed that the functionality of dCTCF is significantly affected by the deletion of the N-terminal DD. Additionally, we observed a strong impact on the binding of the dCTCF mutant to chromatin upon deletion of the DD. However, chromatin binding was restored in transgenic flies expressing a chimeric CTCF protein with the DD of hCTCF. Although the chimeric protein exhibited lower expression levels than those of the dCTCF variants, it efficiently bound to chromatin similarly to the wild type (wt) protein. CONCLUSIONS: Our findings suggest that one of the evolutionarily conserved functions of the unstructured N-terminal dimerization domain is to recruit dCTCF to its genomic sites in vivo.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Humanos , Animais Geneticamente Modificados/metabolismo , Fator de Ligação a CCCTC/metabolismo , Cromatina/metabolismo , Dimerização , Drosophila/genética , Drosophila melanogaster/genética , Proteínas de Drosophila/metabolismo , Mamíferos/genética
17.
Sci Rep ; 14(1): 8103, 2024 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-38582880

RESUMO

Antimicrobial resistance genes (ARG), such as extended-spectrum ß-lactamase (ESBL) and carbapenemase genes, are commonly carried on plasmids. Plasmids can transmit between bacteria, disseminate globally, and cause clinically important resistance. Therefore, targeting plasmids could reduce ARG prevalence, and restore the efficacy of existing antibiotics. Cobalt complexes possess diverse biological activities, including antimicrobial and anticancer properties. However, their effect on plasmid conjugation has not been explored yet. Here, we assessed the effect of four previously characterised bis(N-picolinamido)cobalt(II) complexes lacking antibacterial activity on plasmid conjugation in Escherichia coli and Klebsiella pneumoniae. Antimicrobial susceptibility testing of these cobalt complexes confirmed the lack of antibacterial activity in E. coli and K. pneumoniae. Liquid broth and solid agar conjugation assays were used to screen the activity of the complexes on four archetypical plasmids in E. coli J53. The cobalt complexes significantly reduced the conjugation of RP4, R6K, and R388 plasmids, but not pKM101, on solid agar in E. coli J53. Owing to their promising activity, the impact of cobalt complexes was tested on the conjugation of fluorescently tagged extended-spectrum ß-lactamase encoding pCTgfp plasmid in E. coli and carbapenemase encoding pKpQILgfp plasmid in K. pneumoniae, using flow cytometry. The complexes significantly reduced the conjugation of pKpQILgfp in K. pneumoniae but had no impact on pCTgfp conjugation in E. coli. The cobalt complexes did not have plasmid-curing activity, suggesting that they target conjugation rather than plasmid stability. To our knowledge, this is the first study to report reduced conjugation of clinically relevant plasmids with cobalt complexes. These cobalt complexes are not cytotoxic towards mammalian cells and are not antibacterial, therefore they could be optimised and employed as inhibitors of plasmid conjugation.


Assuntos
Anti-Infecciosos , Infecções por Klebsiella , Animais , Ágar , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , beta-Lactamases/genética , Escherichia coli/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Mamíferos/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética
18.
Biochemistry (Mosc) ; 89(2): 313-321, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38622098

RESUMO

AgeMeta is a database that provides systemic and quantitative description of mammalian aging at the level of gene expression. It encompasses transcriptomic changes with age across various tissues of humans, mice, and rats, based on a comprehensive meta-analysis of 122 publicly available gene expression datasets from 26 studies. AgeMeta provides an intuitive visual interface for quantification of aging-associated transcriptomics at the level of individual genes and functional groups of genes, allowing easy comparison among various species and tissues. Additionally, all the data in the database can be downloaded and analyzed independently. Overall, this work contributes to the understanding of the complex network of biological processes underlying mammalian aging and supports future advancements in this field. AgeMeta is freely available at: https://age-meta.com/.


Assuntos
Perfilação da Expressão Gênica , Transcriptoma , Ratos , Camundongos , Humanos , Animais , Envelhecimento/genética , Bases de Dados Factuais , Mamíferos/genética
19.
Cell Biochem Funct ; 42(3): e4006, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38622913

RESUMO

Nuclear paraspeckle assembly transcript 1 (NEAT1) is a long noncoding RNA (lncRNA) that is widely expressed in a variety of mammalian cell types. Altered expression levels of the lncRNA NEAT1 have been reported in liver-related disorders including cancer, fatty liver disease, liver fibrosis, viral hepatitis, and hepatic ischemia. lncRNA NEAT1 mostly acts as a competing endogenous RNA (ceRNA) to sponge various miRNAs (miRs) to regulate different functions. In regard to hepatic cancers, the elevated expression of NEAT1 has been reported to have a relation with the proliferation, migration, angiogenesis, apoptosis, as well as epithelial-mesenchymal transition (EMT) of cancer cells. Furthermore, NEAT1 upregulation has contributed to the pathogenesis of other liver diseases such as fibrosis. In this review, we summarize and discuss the molecular mechanisms by which NEAT1 contributes to liver-related disorders including acute liver failure, nonalcoholic fatty liver disease (NAFLD), liver fibrosis, and liver carcinoma, providing novel insights and introducing NEAT1 as a potential therapeutic target in these diseases.


Assuntos
MicroRNAs , Hepatopatia Gordurosa não Alcoólica , RNA Longo não Codificante , Animais , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Cirrose Hepática/genética , Hepatopatia Gordurosa não Alcoólica/genética , Fibrose , Proliferação de Células/genética , Mamíferos/genética , Mamíferos/metabolismo
20.
Nat Commun ; 15(1): 2901, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38575571

RESUMO

Simultaneous multi-target detection and multi-site gene editing are two key factors restricting the development of disease diagnostic and treatment technologies. Despite numerous explorations on the source, classification, functional features, crystal structure, applications and engineering of CRISPR-Cas13a, all reports use the contiguous target RNA activation paradigm that only enables single-target detection in vitro and one-site gene editing in vivo. Here we propose a noncontiguous target RNA activation paradigm of Cas13a and establish a CRISPR-Cas13a Gemini System composed of two Cas13a:crRNA binary complexes, which can provide rapid, simultaneous, highly specific and sensitive detection of two RNAs in a single readout, as well as parallel dual transgene knockdown. CRISPR-Cas13a Gemini System are demonstrated in the detection of two miRNAs (miR-155 and miR-375) for breast cancer diagnosis and two small RNAs (EBER-1 and EBER-2) for Epstein-Barr virus diagnosis using multiple diagnostic platforms, including fluorescence and colorimetric-based lateral flow systems. We also show that CRISPR-Cas13a Gemini System can knockdown two foreign genes (EGFP and mCherry transcripts) in mammalian cells simultaneously. These findings suggest the potential of highly effective and simultaneous detection of multiple biomarkers and gene editing of multiple sites.


Assuntos
Infecções por Vírus Epstein-Barr , MicroRNAs , Animais , Humanos , RNA/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Sistemas CRISPR-Cas/genética , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , Mamíferos/genética
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