Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA399090 | ENA |
REPOSITORIES: ENA
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Project description:Xist requires Repeat-A, a protein binding module in its first two kilobases (2kb), to repress transcription. We report that in mouse embryonic stem cells (ESCs), when expressed as a standalone transcript, the first 2kb of Xist (Xist-2kb) represses the expression of adjacent genes not at the transcriptional level, but by sequestering their mRNA on chromatin. Sequestration does not spread beyond adjacent genes, requires the same sequence elements in Repeat-A that full-length Xist requires to repress transcription, and can be induced by lncRNAs whose sequence composition is related to Xist-2kb. We did not detect local sequestration by full-length Xist, but did detect it by mutant forms of Xist with attenuated transcriptional silencing capability. SPEN and RBM15, Repeat-A binding proteins required for Xist-induced transcriptional silencing, also bound Repeat-A in Xist-2kb, but neither protein was necessary for sequestration. Thus, in mouse ESCs, expression of a 5¢ fragment of Xist that contains Repeat-A can repress gene expression by sequestering nearby mRNAs on chromatin, but it does not induce transcriptional silencing. Rather, Xist-induced transcriptional silencing requires synergy between Repeat-A and additional sequence elements in Xist. These results highlight an important gap in our understanding of the mechanisms through which Repeat-A functions within Xist. We discuss how the mechanisms that underpin sequestration may be relevant to the biology of Xist and of other lncRNAs.
2019-05-07 | GSE120197 | GEO
Project description:Many large noncoding RNAs (lncRNAs) regulate chromatin, but the mechanisms by which they localize to genomic targets remain unexplored. Here we investigate the localization mechanisms of Xist during X-chromosome inactivation (XCI), a paradigm of lncRNA-mediated chromatin regulation. During the maintenance of XCI, Xist binds broadly across the X-chromosome. During initiation of XCI, Xist initially transfers to distal regions across the X-chromosome that are not defined by specific sequences. Instead, Xist identifies these regions by exploiting the three-dimensional conformation of the X-chromosome. Xist initially accumulates on the periphery of actively transcribed regions and requires its silencing domain to spread across active regions. This suggests a model where Xist coats the entire X-chromosome by searching in three dimensions, modifying chromosome structure, and spreading to newly accessible locations. We examined the genomic localization of the Xist lncRNA using RNA Antisense Purification (RAP) in multiple cell contexts: 1) differentiated female cells (MLFs); 2) a time-course of Xist localization in male embryonic stem (ES) cells where the endogenous Xist promoter is replaced by a tet-inducible one (pSM33); 3) a time-course of Xist localization in differentiating female ES cells (F1 2-1); and 4) wild-type (delXF6) and A-repeat deletion (delSXC9) Xist transgenes incorporated into the Hprt locus under the control of a tet-inducible promoter.
2013-05-30 | E-GEOD-46918 | biostudies-arrayexpress
Project description: Not available
| S-EPMC8784167 | biostudies-literature
Project description:We show that Spen, an Xist binding repressor protein essential for XCI, binds to ancient retroviral RNA transcribed genome-wide, performing a surveillance role to recruit chromatin silencing machinery to these parasitic loci. Spen inactivation leads to de-repression of endogenous retroviral (ERV) elements in embryonic stem cells, with gain of chromatin accessibility, active histone modifications, and ERV RNA transcription. Spen binds directly to ERV RNAs that are highly similar to the A-repeat of Xist, a region critical for Xist-mediated gene silencing. ERV RNA and Xist A-repeat bind the RRM3 domain of Spen in a competitive manner and insertion of an ERV into an A-repeat deficient Xist rescues binding of Xist RNA to Spen.
2020-05-16 | GSE131412 | GEO
Project description:We show that Spen, an Xist binding repressor protein essential for XCI, binds to ancient retroviral RNA transcribed genome-wide, performing a surveillance role to recruit chromatin silencing machinery to these parasitic loci. Spen inactivation leads to de-repression of endogenous retroviral (ERV) elements in embryonic stem cells, with gain of chromatin accessibility, active histone modifications, and ERV RNA transcription. Spen binds directly to ERV RNAs that are highly similar to the A-repeat of Xist, a region critical for Xist-mediated gene silencing. ERV RNA and Xist A-repeat bind the RRM3 domain of Spen in a competitive manner and insertion of an ERV into an A-repeat deficient Xist rescues binding of Xist RNA to Spen.
2020-05-16 | GSE131374 | GEO
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
2004-01-02 | GSE887 | GEO
Project description: Not available
| S-EPMC395764 | biostudies-literature
Project description: Not available
| S-EPMC4490682 | biostudies-literature
Project description: Not available
| S-EPMC5728457 | biostudies-literature
Project description:We show that Spen, an Xist binding repressor protein essential for XCI, binds to ancient retroviral RNA transcribed genome-wide, performing a surveillance role to recruit chromatin silencing machinery to these parasitic loci. Spen inactivation leads to de-repression of endogenous retroviral (ERV) elements in embryonic stem cells, with gain of chromatin accessibility, active histone modifications, and ERV RNA transcription. Spen binds directly to ERV RNAs that are highly similar to the A-repeat of Xist, a region critical for Xist-mediated gene silencing. ERV RNA and Xist A-repeat bind the RRM3 domain of Spen in a competitive manner and insertion of an ERV into an A-repeat deficient Xist rescues binding of Xist RNA to Spen.
2020-05-16 | GSE131376 | GEO