Tye7 regulates yeast Ty1 retrotransposon sense and antisense transcription in response to adenylic nucleotides stress
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE28579 | GEO | 2012/02/10
SECONDARY ACCESSION(S): PRJNA138995
REPOSITORIES: GEO
Similar Datasets
Project description:We investigated the effects of adenine starvation on the global yeast transcriptome. In this work, global transcription analyses were combined with measurements of intracellular nucleotides pools by HPLC. The bas1delta strain grown with or without adenine was compared to the WT strain grown with or without adenine. For each comparison, we performed 2 technical replicates, swapping dyes.
2012-02-10 | E-GEOD-28579 | biostudies-arrayexpress
Project description:Transposable elements play a fundamental role in genome evolution. It is proposed that their mobility, activated under stress, induces mutations that could confer advantages to the host organism. Transcription of the Ty1 LTR-retrotransposon of Saccharomyces cerevisiae is activated in response to a severe deficiency in adenylic nucleotides. Here, we show that Ty2 and Ty3 are also stimulated under these stress conditions, revealing the simultaneous activation of three active Ty retrotransposon families. We demonstrate that Ty1 activation in response to adenylic nucleotide depletion requires the DNA-binding transcription factor Tye7. Ty1 is transcribed in both sense and antisense directions. We identify three Tye7 potential binding sites in the region of Ty1 DNA sequence where antisense transcription starts. We show that Tye7 binds to Ty1 DNA and regulates Ty1 antisense transcription. Altogether, our data suggest that, in response to adenylic nucleotide reduction, TYE7 is induced and activates Ty1 mRNA transcription, possibly by controlling Ty1 antisense transcription. We also provide the first evidence that Ty1 antisense transcription can be regulated by environmental stress conditions, pointing to a new level of control of Ty1 activity by stress, as Ty1 antisense RNAs play an important role in regulating Ty1 mobility at both the transcriptional and post-transcriptional stages.
| S-EPMC3384299 | biostudies-literature
Project description:Ty1 is one of the many transposons in the budding yeast Saccharomyces cerevisiae. The life-cycle of Ty1 shows numerous similarities with that of retroviruses, e.g. the initially synthesized polyprotein precursor undergoes proteolytic processing by the protease. The retroviral proteases have become important targets of current antiretroviral therapies due to the critical role of the limited proteolysis of Gag-Pol polyprotein in the replication cycle and they therefore belong to the most well-studied enzymes. Comparative analyses of retroviral and retroviral-like proteases can help to explore the key similarities and differences which may help understanding how resistance is developed against protease inhibitors, but the available information about the structural and biochemical characteristics of retroviral-like, and especially retrotransposon, proteases is limited. To investigate the main characteristics of Ty1 retrotransposon protease of Saccharomyces cerevisiae, untagged and His6-tagged forms of Ty1 protease were expressed in E. coli. After purification of the recombinant proteins, activity measurements were performed using synthetic oligopeptide and fluorescent recombinant protein substrates, which represented the wild-type and the modified forms of naturally occurring cleavage sites of the protease. We investigated the dependence of enzyme activity on different reaction conditions (pH, temperature, ionic strength, and urea concentration), and determined enzyme kinetic parameters for the studied substrates. Inhibitory potentials of 10 different protease inhibitors were also tested. Ty1 protease was not inhibited by the inhibitors which have been designed against human immunodeficiency virus type 1 protease and are approved as antiretroviral therapeutics. A quaternary structure of homodimeric Ty1 protease was proposed based on homology modeling, and this structure was used to support interpretation of experimental results and to correlate some structural and biochemical characteristics with that of other retroviral proteases.
| S-EPMC6952103 | biostudies-literature
Project description:We investigated the effects of the variation in intracellular adenylic nucleotides pools due to the absence of the adenylate kinase Adk1p on the global yeast transcriptome. In this work, global transcription analyses were combined to measurements of intracellular nucleotides pools by HPLC. Keywords: Comparative genomic transcription on total RNA from cells containing or not Adk1p.
2008-04-17 | GSE9553 | GEO
Project description:A novel form of copy number control (CNC) helps maintain a low number of Ty1 retrovirus-like transposons in the Saccharomyces genome. Ty1 produces an alternative transcript that encodes p22, a trans-dominant negative inhibitor of Ty1 retrotransposition whose sequence is identical to the C-terminal half of Gag. The level of p22 increases with copy number and inhibits normal Ty1 virus-like particle (VLP) assembly and maturation through interactions with full length Gag. A forward genetic screen for CNC-resistant (CNCR) mutations in Ty1 identified missense mutations in GAG that restore retrotransposition in the presence of p22. Some of these mutations map within a predicted UBN2 domain found throughout the Ty1/copia family of long terminal repeat retrotransposons, and others cluster within a central region of Gag that is referred to as the CNCR domain. We generated multiple alignments of yeast Ty1-like Gag proteins and found that some Gag proteins, including those of the related Ty2 elements, contain non-Ty1 residues at multiple CNCR sites. Interestingly, the Ty2-917 element is resistant to p22 and does not undergo a Ty1-like form of CNC. Substitutions conferring CNCR map within predicted helices in Ty1 Gag that overlap with conserved sequence in Ty1/copia, suggesting that p22 disturbs a central function of the capsid during VLP assembly. When hydrophobic residues within predicted helices in Gag are mutated, Gag level remains unaffected in most cases yet VLP assembly and maturation is abnormal. Gag CNCR mutations do not alter binding to p22 as determined by co-immunoprecipitation analyses, but instead, exclude p22 from Ty1 VLPs. These findings suggest that the CNCR alleles enhance retrotransposition in the presence of p22 by allowing productive Gag-Gag interactions during VLP assembly. Our work also expands the strategies used by retroviruses for developing resistance to Gag-like restriction factors to now include retrotransposons.
| S-EPMC4599808 | biostudies-literature
Project description:Ty1, a long terminal repeat retrotransposon of Saccharomyces, is structurally and functionally related to retroviruses. However, a differentiating aspect between these retroelements is the diversity of the replication strategies used by long terminal repeat retrotransposons. To understand the structural organization of cis-acting elements present on Ty1 genomic RNA from the GAG region that control reverse transcription, we applied chemoenzymatic probing to RNA/tRNA complexes assembled in vitro and to the RNA in virus-like particles. By comparing different RNA states, our analyses provide a comprehensive structure of the primer-binding site, a novel pseudoknot adjacent to the primer-binding sites, three regions containing palindromic sequences that may be involved in RNA dimerization or packaging and candidate protein interaction sites. In addition, we determined the impact of a novel form of transposon control based on Ty1 antisense transcripts that associate with virus-like particles. Our results support the idea that antisense RNAs inhibit retrotransposition by targeting Ty1 protein function rather than annealing with the RNA genome.
| S-EPMC3592414 | biostudies-literature
Project description:Transposable elements impact genome function by altering gene expression and causing chromosome rearrangements. As a result, organisms have evolved mechanisms, such as RNA-interference, to minimize the level of transposition. However, organisms without the conserved RNAi pathways, like Saccharomyces cerevisiae, must use other mechanisms to prevent transposon movement. Here, we provide evidence that antisense (AS) RNAs from the retrovirus-like element Ty1 inhibit retrotransposition posttranslationally in Saccharomyces. Multiple Ty1AS transcripts overlap Ty1 sequences necessary for copy number control (CNC) and inhibit transposition in trans. Altering Ty1 copy number or deleting sequences in the CNC region that are required for reverse transcription affect Ty1AS RNA level and Ty1 movement. Ty1AS RNAs are enriched in virus-like particles, and are associated with a dramatic decrease in the level of integrase, less reverse transcriptase, and an inability to synthesize Ty1 cDNA. Thus, Ty1AS RNAs are part of an intrinsic mechanism that limits retrotransposition by reducing the level of proteins required for replication and integration.
| S-EPMC2735561 | biostudies-literature
Project description:A universal feature of retroelement propagation is the formation of distinct nucleoprotein complexes mediated by the Gag capsid protein. The Ty1 retrotransposon Gag protein from Saccharomyces cerevisiae lacks sequence homology with retroviral Gag, but is functionally related. In addition to capsid assembly functions, Ty1 Gag promotes Ty1 RNA dimerization and cyclization and initiation of reverse transcription. Direct interactions between Gag and retrotransposon genomic RNA (gRNA) are needed for Ty1 replication, and mutations in the RNA-binding domain disrupt nucleation of retrosomes and assembly of functional virus-like particles (VLPs). Unlike retroviral Gag, the specificity of Ty1 Gag-RNA interactions remain poorly understood. Here we use microscale thermophoresis (MST) and electrophoretic mobility shift assays (EMSA) to analyze interactions of immature and mature Ty1 Gag with RNAs. The salt-dependent experiments showed that Ty1 Gag binds with high and similar affinity to different RNAs. However, we observed a preferential interaction between Ty1 Gag and Ty1 RNA containing a packaging signal (Psi) in RNA competition analyses. We also uncover a relationship between Ty1 RNA structure and Gag binding involving the pseudoknot present on Ty1 gRNA. In all likelihood, the differences in Gag binding affinity detected in vitro only partially explain selective Ty1 RNA packaging into VLPs in vivo.
| S-EPMC8396678 | biostudies-literature
Project description:BackgroundLTR-retrotransposons became functional neogenes through evolution by acquiring promoter sequences, regulatory elements and sequence modification. Mammalian retrotransposon transcripts (Mart1-9), also called sushi-ichi-related retrotransposon-homolog (SIRH) genes, are a class of Ty3/gypsy LTR-retroelements showing moderate homology to the sushi-ichi LTR-retrotransposon in pufferfish. Rtl1/Mart1 and Peg10/Mart2 expression in mouse placenta and demonstration of their functional roles during placental development exemplifies their importance in cellular processes. In this study, we analyzed all eleven mouse Mart genes from the blastocyst stage and throughout placentogenesis in order to gain information about their expression and regulation.ResultsQuantitative PCR, in situ hybridization (ISH) and immunoblotting showed various expression patterns of the 11 mouse Mart genes through different placental stages. Zcchc5/Mart3, Zcchc16/ Mart4 and Rgag1/Mart9 expression was undetectable. Rtl1/Mart1, Peg10/Mart2, Rgag4/Mart5 - Cxx1a,b,c/Mart8b,c,a gene expression was very low at the blastocyst stage. Later placental stages showed an increase of expression for Rtl1/Mart1, Rgag4/Mart5 - Cxx1a,b,c/Mart8b,c,a, the latter up to 1,489 molecules/ng cDNA at E9.5. From our recently published findings Peg10/Mart2 was the most highly expressed Mart gene. ISH demonstrated sense and antisense transcript co-localization of Rgag4/Mart5 to Cxx1a,b,c/Mart8b,c,a in trophoblast subtypes at the junctional zone, with an accumulation of antisense transcripts in the nuclei. To validate these results, we developed a TAG-aided sense/antisense transcript detection (TASA-TD) method, which verified sense and antisense transcripts for Rtl1/Mart1, Rgag4/Mart5 - Cxx1a,b,c/Mart8b,c,a. Except for Rtl1/Mart1 and Cxx1a,b/Mart8b,c all other Mart genes showed a reduced amount of antisense transcripts. Northern blot and 5' and 3' RACE confirmed both sense and antisense transcripts for Ldoc1/Mart7 and Cxx1a,b,c/Mart8b,c,a. Immunoblotting demonstrated a single protein throughout all placental stages for Ldoc1/Mart7, but for Cxx1a,b,c/Mart8b,c,a a switch occurred from a 57 kDa protein at E10.5 and E14.5 to a 25 kDa protein at E16.5 and E18.5.ConclusionsRNA and protein detection of mouse Mart genes support neo-functionalization of retrotransposons in mammalian genomes. Undetectable expression of Zcchc5/Mart3, Zcchc16/Mart4 and Rgag1/Mart9 indicate no role during mouse placentogenesis. Rgag4/Mart5 to Cxx1a,b,c/Mart8b,c,a gene expression support a role for differentiation from the ectoplacental cone. Mart antisense transcripts and protein alterations predict unique and complex molecular regulation in a time directed manner throughout mouse placentogenesis.
| S-EPMC4340606 | biostudies-literature
Project description:We investigated the role of Bas1p in the transcriptional response due to AICAR and SAICAR accumulation. In this work, global transcription analyses were combined to measurements of intracellular nucleotides pools by HPLC. Keywords: Comparative genomic transcription analysis on total RNA from cells accumulating AICAR and SAICAR in a bas1 deletion context.
2009-05-15 | GSE13187 | GEO