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1.
medRxiv ; 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38313291

RESUMO

Objective: To investigate the relationship between vaccination rates and excess mortality during distinct waves of SARS-CoV-2 variant-specific infections, while considering a state's GDP per capita. Methods: We ranked U.S. states by vaccination rates and GDP and employed the CDC's excess mortality model for regression and odds ratio analysis. Results: Regression analysis reveals that both vaccination and GDP are significant factors related to mortality when considering the entire U.S. population. Notably, in wealthier states (with GDP above $65,000), excess mortality is primarily driven by slow vaccination rates, while in less affluent states, low GDP plays a major role. Odds ratio analysis demonstrates an almost twofold increase in mortality linked to the Delta and Omicron BA.1 virus variants in states with the slowest vaccination rates compared to those with the fastest (OR 1.8, 95% CI 1.7-1.9, p < 0.01). However, this gap disappeared in the post-Omicron BA.1 period. Conclusion: The interplay between slow vaccination and low GDP per capita drives high mortality.

2.
Front Immunol ; 14: 1151311, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37483606

RESUMO

Aim: To evaluate the effect of vaccination/booster administration dynamics on the reduction of excess mortality during COVID-19 infection waves in European countries. Methods: We selected twenty-nine countries from the OurWorldInData project database according to their population size of more than one million and the availability of information on dominant SARS-CoV-2 variants during COVID-19 infection waves. After selection, we categorized countries according to their "faster" or "slower" vaccination rates. The first category included countries that reached 60% of vaccinated residents by October 2021 and 70% by January 2022. The second or "slower" category included all other countries. In the first or "faster" category, two groups, "boosters faster'' and "boosters slower" were created. Pearson correlation analysis, linear regression, and chi-square test for categorical data were used to identify the association between vaccination rate and excess mortality. We chose time intervals corresponding to the dominance of viral variants: Wuhan, Alpha, Delta, and Omicron BA.1/2. Results and discussion: The "faster" countries, as opposed to the "slower" ones, did better in protecting their residents from mortality during all periods of the SARS-CoV-2 pandemic and even before vaccination. Perhaps higher GDP per capita contributed to their better performance throughout the pandemic. During mass vaccination, when the Delta variant prevailed, the contrast in mortality rates between the "faster" and "slower" categories was strongest. The average excess mortality in the "slower" countries was nearly 5 times higher than in the "faster" countries, and the odds ratio (OR) was 4.9 (95% CI 4.4 to 5.4). Slower booster rates were associated with significantly higher mortality during periods dominated by Omicron BA.1 and BA.2, with an OR of 2.6 (CI 95%. 2.1 to 3.3). Among the European countries we analyzed, Denmark, Norway, and Ireland did best, with a pandemic mortality rate of 0.1% of the population or less. By comparison, Bulgaria, Serbia, and Russia had a much higher mortality rate of up to 1% of the population. Conclusion: Thus, slow vaccination and booster administration was a major factor contributing to an order of magnitude higher excess mortality in "slower" European countries compared to more rapidly immunized countries.


Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Pandemias , Vacinação
3.
medRxiv ; 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-37090496

RESUMO

Aim To evaluate the effect of vaccination/booster administration dynamics on the reduction of excess mortality during COVID-19 infection waves in European countries. Methods We selected twenty-nine countries from the OurWorldInData project database according to their population size of more than one million and the availability of information on dominant SARS-CoV-2 variants during COVID-19 infection waves. After selection, we categorized countries according to their ″faster″ or ″slower″ vaccination rates. The first category included countries that reached 60% of vaccinated residents by October 2021 and 70% by January 2022. The second or ″slower″ category included all other countries. In the first or ″faster″ category, two groups, ″boosters faster'' and ″boosters slower″ were created. Pearson correlation analysis, linear regression, and chi-square test for categorical data were used to identify the association between vaccination rate and excess mortality. We chose time intervals corresponding to the dominance of viral variants: Wuhan, Alpha, Delta, and Omicron BA.1/2. Results The ″faster″ countries, as opposed to the ″slower″ ones, did better in protecting their residents from mortality during all periods of the SARS-CoV-2 pandemic and even before vaccination. Perhaps higher GDP per capita contributed to their better performance throughout the pandemic. During mass vaccination, when the Delta variant prevailed, the contrast in mortality rates between the ″faster″ and ″slower″ categories was strongest. The average excess mortality in the ″slower″ countries was nearly 5 times higher than in the ″faster″ countries, and the odds ratio (OR) was 4.9 (95% CI 4.4 to 5.4). Slower booster rates were associated with significantly higher mortality during periods dominated by Omicron BA.1 and BA.2, with an OR of 2.6 (CI 95%. 2.1 to 3.3). Among the European countries we analyzed, Denmark, Norway, and Ireland did best, with a pandemic mortality rate of 0.1% of the population or less. By comparison, Bulgaria, Serbia, and Russia had a much higher mortality rate of up to 1% of the population. Thus, slow vaccination and booster administration was a major factor contributing to an order of magnitude higher excess mortality in ″slower″ European countries compared to more rapidly immunized countries.

4.
Cell Mol Life Sci ; 80(5): 121, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37043028

RESUMO

Although they are organelles without a limiting membrane, nucleoli have an exclusive structure, built upon the rDNA-rich acrocentric short arms of five human chromosomes (nucleolar organizer regions or NORs). This has raised the question: what are the structural features of a chromosome required for its inclusion in a nucleolus? Previous work has suggested that sequences adjacent to the tandemly repeated rDNA repeat units (DJ, distal junction sequence) may be involved, and we have extended such studies by addressing several issues related to the requirements for the association of NORs with nucleoli. We exploited both a set of somatic cell hybrids containing individual human acrocentric chromosomes and a set of Human Artificial Chromosomes (HACs) carrying different parts of a NOR, including an rDNA unit or DJ or PJ (proximal junction) sequence. Association of NORs with nucleoli was increased when constituent rDNA was transcribed and may be also affected by the status of heterochromatin blocks formed next to the rDNA arrays. Furthermore, our data suggest that a relatively small size DJ region, highly conserved in evolution, is also involved, along with the rDNA repeats, in the localization of p-arms of acrocentric chromosomes in nucleoli. Thus, we infer a cooperative action of rDNA sequence-stimulated by its activity-and sequences distal to rDNA contributing to incorporation into nucleoli. Analysis of NOR sequences also identified LncRNA_038958 in the DJ, a candidate transcript with the region of the suggested promoter that is located close to the DJ/rDNA boundary and contains CTCF binding sites. This LncRNA may affect RNA Polymerase I and/or nucleolar activity. Our findings provide the basis for future studies to determine which RNAs and proteins interact critically with NOR sequences to organize the higher-order structure of nucleoli and their function in normal cells and pathological states.


Assuntos
Região Organizadora do Nucléolo , RNA Longo não Codificante , Humanos , Região Organizadora do Nucléolo/genética , Região Organizadora do Nucléolo/metabolismo , DNA Ribossômico/genética , RNA Longo não Codificante/metabolismo , Nucléolo Celular/genética , Nucléolo Celular/metabolismo , Cromossomos Humanos/metabolismo
5.
Nucleic Acids Res ; 50(17): 10093-10109, 2022 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-36062564

RESUMO

Increasing numbers of small, regulatory RNAs (sRNAs) corresponding to 3' untranslated regions (UTR) are being discovered in bacteria. One such sRNA, denoted GlnZ, corresponds to the 3' UTR of the Escherichia coli glnA mRNA encoding glutamine synthetase. Several forms of GlnZ, processed from the glnA mRNA, are detected in cells growing with limiting ammonium. GlnZ levels are regulated transcriptionally by the NtrC transcription factor and post-transcriptionally by RNase III. Consistent with the expression, E. coli cells lacking glnZ show delayed outgrowth from nitrogen starvation compared to wild type cells. Transcriptome-wide RNA-RNA interactome datasets indicated that GlnZ binds to multiple target RNAs. Immunoblots and assays of fusions confirmed GlnZ-mediated repression of glnP and sucA, encoding proteins that contribute to glutamine transport and the citric acid cycle, respectively. Although the overall sequences of GlnZ from E. coli K-12, Enterohemorrhagic E. coli and Salmonella enterica have significant differences due to various sequence insertions, all forms of the sRNA were able to regulate the two targets characterized. Together our data show that GlnZ impacts growth of E. coli under low nitrogen conditions by modulating genes that affect carbon and nitrogen flux.


Assuntos
Compostos de Amônio , Microbioma Gastrointestinal , Pequeno RNA não Traduzido , Regiões 3' não Traduzidas , Carbono/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Glutamato-Amônia Ligase/genética , Glutamina/genética , Glutamina/metabolismo , Nitrogênio/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/metabolismo , Ribonuclease III/metabolismo , Fatores de Transcrição/metabolismo
6.
Nucleic Acids Res ; 50(2): e11, 2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-34791389

RESUMO

The choice of guide RNA (gRNA) for CRISPR-based gene targeting is an essential step in gene editing applications, but the prediction of gRNA specificity remains challenging. Lack of transparency and focus on point estimates of efficiency disregarding the information on possible error sources in the model limit the power of existing Deep Learning-based methods. To overcome these problems, we present a new approach, a hybrid of Capsule Networks and Gaussian Processes. Our method predicts the cleavage efficiency of a gRNA with a corresponding confidence interval, which allows the user to incorporate information regarding possible model errors into the experimental design. We provide the first utilization of uncertainty estimation in computational gRNA design, which is a critical step toward accurate decision-making for future CRISPR applications. The proposed solution demonstrates acceptable confidence intervals for most test sets and shows regression quality similar to existing models. We introduce a set of criteria for gRNA selection based on off-target cleavage efficiency and its variance and present a collection of pre-computed gRNAs for human chromosome 22. Using Neural Network Interpretation methods, we show that our model rediscovers an established biological factor underlying cleavage efficiency, the importance of the seed region in gRNA.


Assuntos
Sistemas CRISPR-Cas , Aprendizado Profundo , Edição de Genes , Marcação de Genes , RNA Guia de Cinetoplastídeos/genética , Algoritmos , Edição de Genes/métodos , Marcação de Genes/métodos , Genômica/métodos , Humanos , Redes Neurais de Computação , Reprodutibilidade dos Testes
7.
Nucleic Acids Res ; 49(18): 10328-10346, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34570232

RESUMO

Pervasive transcription of eukaryotic genomes results in expression of long non-coding RNAs (lncRNAs) most of which are poorly conserved in evolution and appear to be non-functional. However, some lncRNAs have been shown to perform specific functions, in particular, transcription regulation. Thousands of small open reading frames (smORFs, <100 codons) located on lncRNAs potentially might be translated into peptides or microproteins. We report a comprehensive analysis of the conservation and evolutionary trajectories of lncRNAs-smORFs from the moss Physcomitrium patens across transcriptomes of 479 plant species. Although thousands of smORFs are subject to substantial purifying selection, the majority of the smORFs appear to be evolutionary young and could represent a major pool for functional innovation. Using nanopore RNA sequencing, we show that, on average, the transcriptional level of conserved smORFs is higher than that of non-conserved smORFs. Proteomic analysis confirmed translation of 82 novel species-specific smORFs. Numerous conserved smORFs containing low complexity regions (LCRs) or transmembrane domains were identified, the biological functions of a selected LCR-smORF were demonstrated experimentally. Thus, microproteins encoded by smORFs are a major, functionally diverse component of the plant proteome.


Assuntos
Bryopsida/genética , Fases de Leitura Aberta , Proteoma , RNA Longo não Codificante , Transcriptoma
8.
Sci Rep ; 11(1): 2997, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33542373

RESUMO

The rDNA clusters and flanking sequences on human chromosomes 13, 14, 15, 21 and 22 represent large gaps in the current genomic assembly. The organization and the degree of divergence of the human rDNA units within an individual nucleolar organizer region (NOR) are only partially known. To address this lacuna, we previously applied transformation-associated recombination (TAR) cloning to isolate individual rDNA units from chromosome 21. That approach revealed an unexpectedly high level of heterogeneity in human rDNA, raising the possibility of corresponding variations in ribosome dynamics. We have now applied the same strategy to analyze an entire rDNA array end-to-end from a copy of chromosome 22. Sequencing of TAR isolates provided the entire NOR sequence, including proximal and distal junctions that may be involved in nucleolar function. Comparison of the newly sequenced rDNAs to reference sequence for chromosomes 22 and 21 revealed variants that are shared in human rDNA in individuals from different ethnic groups, many of them at high frequency. Analysis infers comparable intra- and inter-individual divergence of rDNA units on the same and different chromosomes, supporting the concerted evolution of rDNA units. The results provide a route to investigate further the role of rDNA variation in nucleolar formation and in the empirical associations of nucleoli with pathology.


Assuntos
Cromossomos Humanos Par 22/genética , DNA Ribossômico/genética , Genoma Humano/genética , Região Organizadora do Nucléolo/genética , Nucléolo Celular/genética , Clonagem Molecular , Heterogeneidade Genética , Genômica , Humanos , Anotação de Sequência Molecular , Ribossomos/genética
9.
Cell Mol Neurobiol ; 41(5): 1039-1055, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33010019

RESUMO

The opioid receptor (OPR) family comprises the mu-, delta-, and kappa-opioid, and nociceptin receptors that belong to the superfamily of 7-transmembrane spanning G protein-coupled receptors (GPCRs). The mu-opioid receptor is the main target for clinically used opioid analgesics, and its biology has been extensively studied. The N-terminally truncated 6TM receptors isoform produced through alternative splicing of the OPRM1 gene displays unique signaling and analgesic properties, but it is unclear if other OPRs have the same ability. In this study, we have built a comprehensive map of alternative splicing events that produce 6TM receptor variants in all the OPRs and demonstrated their evolutionary conservation. We then obtained evidence for their translation through ribosomal footprint analysis. We discovered that N-terminally truncated 6TM GPCRs are rare in the human genome and OPRs are overrepresented in this group. Finally, we also observed a significant enrichment of 6TM GPCR genes among genes associated with pain, psychiatric disorders, and addiction. Understanding the biology of 6TM receptors and leveraging this knowledge for drug development should pave the way for novel therapies.


Assuntos
Processamento Alternativo/genética , Sequência Conservada/genética , Receptores Opioides delta/genética , Receptores Opioides kappa/genética , Receptores Opioides mu/genética , Receptores Opioides/genética , Animais , Linhagem Celular Tumoral , Bases de Dados Genéticas , Variação Genética/genética , Humanos , Macaca , Camundongos , Especificidade da Espécie , Receptor de Nociceptina
11.
Cancers (Basel) ; 12(12)2020 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-33291506

RESUMO

The effectiveness of oncolytic virotherapy in cancer treatment depends on several factors, including successful virus delivery to the tumor, ability of the virus to enter the target malignant cell, virus replication, and the release of progeny virions from infected cells. The multi-stage process is influenced by the efficiency with which the virus enters host cells via specific receptors. This review describes natural and artificial receptors for two oncolytic paramyxoviruses, nonpathogenic measles, and Sendai viruses. Cell entry receptors are proteins for measles virus (MV) and sialylated glycans (sialylated glycoproteins or glycolipids/gangliosides) for Sendai virus (SeV). Accumulated published data reviewed here show different levels of expression of cell surface receptors for both viruses in different malignancies. Patients whose tumor cells have low or no expression of receptors for a specific oncolytic virus cannot be successfully treated with the virus. Recent published studies have revealed that an expression signature for immune genes is another important factor that determines the vulnerability of tumor cells to viral infection. In the future, a combination of expression signatures of immune and receptor genes could be used to find a set of oncolytic viruses that are more effective for specific malignancies.

12.
Elife ; 92020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33112233

RESUMO

Long noncoding RNAs (lncRNAs) are often associated with polysomes, indicating coding potential. However, only a handful of endogenous proteins encoded by putative lncRNAs have been identified and assigned a function. Here, we report the discovery of a putative gastrointestinal-tract-specific lncRNA (LINC00675) that is regulated by the pioneer transcription factor FOXA1 and encodes a conserved small protein of 79 amino acids which we termed FORCP (FOXA1-Regulated Conserved Small Protein). FORCP transcript is undetectable in most cell types but is abundant in well-differentiated colorectal cancer (CRC) cells where it functions to inhibit proliferation, clonogenicity, and tumorigenesis. The epitope-tagged and endogenous FORCP protein predominantly localizes to the endoplasmic reticulum (ER). In response to ER stress, FORCP depletion results in decreased apoptosis. Our findings on the initial characterization of FORCP demonstrate that FORCP is a novel, conserved small protein encoded by a mis-annotated lncRNA that regulates apoptosis and tumorigenicity in well-differentiated CRC cells.


Assuntos
Apoptose/genética , Carcinogênese/genética , Neoplasias Colorretais/genética , Fator 3-alfa Nuclear de Hepatócito/metabolismo , RNA Longo não Codificante/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/patologia , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático , Trato Gastrointestinal/metabolismo , Genes Reporter , Fator 3-alfa Nuclear de Hepatócito/genética , Humanos , Anotação de Sequência Molecular , Especificidade de Órgãos , RNA Longo não Codificante/genética
14.
F1000Res ; 8: 1000, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31448109

RESUMO

The differences between high risk and low risk human papillomaviruses (HR-HPV and LR-HPV, respectively) that contribute to the tumorigenic potential of HR-HPV are not well understood but can be expected to involve the HPV oncoproteins, E6 and E7. We combine genome comparison and machine learning techniques to identify a previously unnoticed insert near the 3'-end of the E6 oncoprotein gene that is unique to HR-HPV. Analysis of the insert sequence suggests that it exerts a dual effect, by creating a PDZ domain-binding motif at the C-terminus of E6, as well as eliminating the overlap between the E6 and E7 coding regions in HR-HPV. We show that, as a result, the insert might enable coupled termination-reinitiation of the E6 and E7 genes, supported by motifs complementary to the human 18S rRNA. We hypothesize that the added functionality of E6 and positive regulation of E7 expression jointly account for the tumorigenic potential of HR-HPV.


Assuntos
Proteínas Oncogênicas Virais , Papillomaviridae , Carcinogênese , Humanos , Papillomaviridae/genética , Papillomaviridae/patogenicidade , Medição de Risco
15.
Mol Neurobiol ; 56(4): 2855-2869, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30066306

RESUMO

The delta-opioid receptor (DOPr) participates in mediating the effects of opioid analgesics. However, no selective agonists have entered clinical care despite potential to ameliorate many neurological and psychiatric disorders. In an effort to address the drug development challenges, the functional contribution of receptor isoforms created by alternative splicing of the three-exonic coding gene, OPRD1, has been overlooked. We report that the gene is transcriptionally more diverse than previously demonstrated, producing novel protein isoforms in humans and mice. We provide support for the functional relevance of splice variants through context-dependent expression profiling (tissues, disease model) and conservation of the transcriptional landscape in closely related vertebrates. The conserved alternative transcriptional events have two distinct patterns. First, cassette exon inclusions between exons 1 and 2 interrupt the reading frame, producing truncated receptor fragments comprising only the first transmembrane (TM) domain, despite the lack of exact exon orthologues between distant species. Second, a novel promoter and transcriptional start site upstream of exon 2 produces a transcript of an N-terminally truncated 6TM isoform. However, a fundamental difference in the exonic landscaping as well as translation and translation products poses limits for modelling the human DOPr receptor system in mice.


Assuntos
Processamento Alternativo/genética , Receptores Opioides delta/genética , Animais , Linhagem Celular Tumoral , Dor Crônica/genética , Dor Crônica/patologia , Sequência Conservada , Modelos Animais de Doenças , Evolução Molecular , Feto/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Biossíntese de Proteínas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Opioides delta/metabolismo , Ribossomos/metabolismo
16.
Mol Microbiol ; 111(1): 131-144, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30276893

RESUMO

In response to low levels of magnesium (Mg2+ ), the PhoQP two component system induces the transcription of two convergent genes, one encoding a 31-amino acid protein denoted MgtS and the second encoding a small, regulatory RNA (sRNA) denoted MgrR. Previous studies showed that the MgtS protein interacts with and stabilizes the MgtA Mg2+ importer to increase intracellular Mg2+ levels, while the MgrR sRNA base pairs with the eptB mRNA thus affecting lipopolysaccharide modification. Surprisingly, we found overexpression of the MgtS protein also leads to induction of the PhoRB regulon. Studies to understand this activation showed that MgtS forms a complex with a second protein, PitA, a cation-phosphate symporter. Given that the additive effect of ∆mgtA and ∆mgtS mutations on intracellular Mg2+ concentrations seen previously is lost in the ∆pitA mutant, we suggest that MgtS binds to and prevents Mg2+ leakage through PitA under Mg2+ -limiting conditions. Consistent with a detrimental role of PitA in low Mg2+ , we also observe MgrR sRNA repression of PitA synthesis. Thus, PhoQP induces the expression of two convergent small genes in response to Mg2+ limitation whose products act to modulate PitA at different levels to increase intracellular Mg2+ .


Assuntos
Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Magnésio/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Transporte de Fosfato/metabolismo , Pequeno RNA não Traduzido/metabolismo , Escherichia coli/genética , Redes Reguladoras de Genes
17.
PLoS One ; 13(6): e0199162, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29928000

RESUMO

Off-target oligoprobe's interaction with partially complementary nucleotide sequences represents a problem for many bio-techniques. The goal of the study was to identify oligoprobe sequence characteristics that control the ratio between on-target and off-target hybridization. To understand the complex interplay between specific and genome-wide off-target (cross-hybridization) signals, we analyzed a database derived from genomic comparison hybridization experiments performed with an Affymetrix tiling array. The database included two types of probes with signals derived from (i) a combination of specific signal and cross-hybridization and (ii) genomic cross-hybridization only. All probes from the database were grouped into bins according to their sequence characteristics, where both hybridization signals were averaged separately. For selection of specific probes, we analyzed the following sequence characteristics: vulnerability to self-folding, nucleotide composition bias, numbers of G nucleotides and GGG-blocks, and occurrence of probe's k-mers in the human genome. Increases in bin ranges for these characteristics are simultaneously accompanied by a decrease in hybridization specificity-the ratio between specific and cross-hybridization signals. However, both averaged hybridization signals exhibit growing trends along with an increase of probes' binding energy, where the hybridization specific signal increases significantly faster in comparison to the cross-hybridization. The same trend is evident for the S function, which serves as a combined evaluation of probe binding energy and occurrence of probe's k-mers in the genome. Application of S allows extracting a larger number of specific probes, as compared to using only binding energy. Thus, we showed that high values of specific and cross-hybridization signals are not mutually exclusive for probes with high values of binding energy and S. In this study, the application of a new set of sequence characteristics allows detection of probes that are highly specific to their targets for array design and other bio-techniques that require selection of specific probes.


Assuntos
Hibridização de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Sequência de Bases , Bases de Dados Genéticas , Genoma , Humanos
18.
Nucleic Acids Res ; 46(13): 6712-6725, 2018 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-29788454

RESUMO

Despite the key role of the human ribosome in protein biosynthesis, little is known about the extent of sequence variation in ribosomal DNA (rDNA) or its pre-rRNA and rRNA products. We recovered ribosomal DNA segments from a single human chromosome 21 using transformation-associated recombination (TAR) cloning in yeast. Accurate long-read sequencing of 13 isolates covering ∼0.82 Mb of the chromosome 21 rDNA complement revealed substantial variation among tandem repeat rDNA copies, several palindromic structures and potential errors in the previous reference sequence. These clones revealed 101 variant positions in the 45S transcription unit and 235 in the intergenic spacer sequence. Approximately 60% of the 45S variants were confirmed in independent whole-genome or RNA-seq data, with 47 of these further observed in mature 18S/28S rRNA sequences. TAR cloning and long-read sequencing enabled the accurate reconstruction of multiple rDNA units and a new, high-quality 44 838 bp rDNA reference sequence, which we have annotated with variants detected from chromosome 21 of a single individual. The large number of variants observed reveal heterogeneity in human rDNA, opening up the possibility of corresponding variations in ribosome dynamics.


Assuntos
Cromossomos Humanos Par 21 , DNA Ribossômico/química , Genes de RNAr , Variação Genética , Animais , Linhagem Celular , Clonagem Molecular , DNA Ribossômico/isolamento & purificação , DNA Espaçador Ribossômico/química , Humanos , Camundongos , Conformação de Ácido Nucleico , Região Organizadora do Nucléolo/química , RNA Ribossômico/química , RNA Ribossômico/metabolismo , Análise de Sequência de DNA
19.
Elife ; 62017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29244021

RESUMO

ß- and γ-cytoplasmic actin are nearly indistinguishable in their amino acid sequence, but are encoded by different genes that play non-redundant biological roles. The key determinants that drive their functional distinction are unknown. Here, we tested the hypothesis that ß- and γ-actin functions are defined by their nucleotide, rather than their amino acid sequence, using targeted editing of the mouse genome. Although previous studies have shown that disruption of ß-actin gene critically impacts cell migration and mouse embryogenesis, we demonstrate here that generation of a mouse lacking ß-actin protein by editing ß-actin gene to encode γ-actin protein, and vice versa, does not affect cell migration and/or organism survival. Our data suggest that the essential in vivo function of ß-actin is provided by the gene sequence independent of the encoded protein isoform. We propose that this regulation constitutes a global 'silent code' mechanism that controls the functional diversity of protein isoforms.


Assuntos
Actinas/genética , Actinas/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Edição de Genes , Camundongos
20.
RNA Biol ; 14(12): 1649-1654, 2017 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-28722509

RESUMO

Comparison of mRNA and protein structures shows that highly structured mRNAs typically encode compact protein domains suggesting that mRNA structure controls protein folding. This function is apparently performed by distinct structural elements in the mRNA, which implies 'fine tuning' of mRNA structure under selection for optimal protein folding. We find that, during evolution, changes in the mRNA folding energy follow amino acid replacements, reinforcing the notion of an intimate connection between the structures of a mRNA and the protein it encodes, and the double encoding of protein sequence and folding in the mRNA.


Assuntos
Adaptação Biológica , Conformação de Ácido Nucleico , Biossíntese de Proteínas , Dobramento de Proteína , RNA Mensageiro/química , RNA Mensageiro/genética , Animais , Evolução Biológica , Humanos , Estabilidade de RNA , Seleção Genética , Relação Estrutura-Atividade
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