Project description:While liganded nuclear receptors are well established to regulate Pol II protein-coding transcription units, their role in regulation of DNA repeats remains largely unknown. Here, we report that ~2-3% of the ~1-200,000 human DR2 Alu repeats, particularly those in proximity to retinoic acid-activated Pol II transcription units, are bound and activated by retinoic acid receptor in human embryonic stem cells, triggering their Pol III-dependent transcription. The non-coding DR2 Alu transcripts are processed in a Dicer-dependent fashion into a series of small RNA products with sizes ranging ~28-65nt and exhibit substantial co-localization with P bodies. These small RNAs cause degradation of a subset of mRNAs critical for the "stem cell" state, which harbor complimentary sequences in their 3' untranslated regions. This regulation requires Ago3- dependent stabilization of full-length and processed DR2 Alu transcripts, and recruitment of Ago3-associated decapping complexes to the target mRNAs. Thus, the RAR/Pol III-dependent DR2 Alu transcriptional program in stem cells serves as a functional complement to the RAR/Pol II-dependent counterpart. ChIP-seq of H3K36me3 samples before and after RA (retinoic acid) treatments.
Project description:While liganded nuclear receptors are well established to regulate Pol II protein-coding transcription units, their role in regulation of DNA repeats remains largely unknown. Here, we report that ~2-3% of the ~1-200,000 human DR2 Alu repeats, particularly those in proximity to retinoic acid-activated Pol II transcription units, are bound and activated by retinoic acid receptor in human embryonic stem cells, triggering their Pol III-dependent transcription. The non-coding DR2 Alu transcripts are processed in a Dicer-dependent fashion into a series of small RNA products with sizes ranging ~28-65nt and exhibit substantial co-localization with P bodies. These small RNAs cause degradation of a subset of mRNAs critical for the "stem cell" state, which harbor complimentary sequences in their 3' untranslated regions. This regulation requires Ago3- dependent stabilization of full-length and processed DR2 Alu transcripts, and recruitment of Ago3-associated decapping complexes to the target mRNAs. Thus, the RAR/Pol III-dependent DR2 Alu transcriptional program in stem cells serves as a functional complement to the RAR/Pol II-dependent counterpart.
Project description:Although liganded nuclear receptors have been established to regulate RNA polymerase II (Pol II)-dependent transcription units, their role in regulating Pol III-transcribed DNA repeats remains largely unknown. Here we report that ~2-3% of the ~100,000-200,000 total human DR2 Alu repeats located in proximity to activated Pol II transcription units are activated by the retinoic acid receptor (RAR) in human embryonic stem cells to generate Pol III-dependent RNAs. These transcripts are processed, initially in aM-BM- DICER-dependent fashion, into small RNAs (~28-65 nt) referred to as repeat-induced RNAs that cause the degradation of a subset of crucial stem-cell mRNAs, includingM-BM- NanogM-BM- mRNA, which modulate exit from the proliferative stem-cell state. This regulation requiresM-BM- AGO3-dependent accumulation of processed DR2 Alu transcripts and the subsequent recruitment ofM-BM- AGO3-associated decapping complexes to the target mRNA. In this way, the RAR-dependent and Pol III-dependent DR2 Alu transcriptional events in stem cells functionally complement the Pol II-dependent neuronal transcriptional program. RNA-sequencing of polyA selected RNA molecules in NTera2/D1 cells and Global Run On (GRO) assay followed by high throughput sequencing (GRO-seq).
Project description:Although liganded nuclear receptors have been established to regulate RNA polymerase II (Pol II)-dependent transcription units, their role in regulating Pol III-transcribed DNA repeats remains largely unknown. Here we report that ~2-3% of the ~100,000-200,000 total human DR2 Alu repeats located in proximity to activated Pol II transcription units are activated by the retinoic acid receptor (RAR) in human embryonic stem cells to generate Pol III-dependent RNAs. These transcripts are processed, initially in a DICER-dependent fashion, into small RNAs (~28-65 nt) referred to as repeat-induced RNAs that cause the degradation of a subset of crucial stem-cell mRNAs, including Nanog mRNA, which modulate exit from the proliferative stem-cell state. This regulation requires AGO3-dependent accumulation of processed DR2 Alu transcripts and the subsequent recruitment of AGO3-associated decapping complexes to the target mRNA. In this way, the RAR-dependent and Pol III-dependent DR2 Alu transcriptional events in stem cells functionally complement the Pol II-dependent neuronal transcriptional program.
2012-12-29 | GSE42563 | GEO
Project description:DICER- and AGO3-dependent generation of retinoic acid-induced DR2 Alu RNAs regulates human stem cell proliferation
Project description:Retinoic Acid Receptors (RARs) bind RA-response elements in regulatory regions of their target genes. While canonical RAREs comprise direct repeats of the consensus 5’-RGKTCA-3’ sequence separated by 1, 2 or 5 nucleotides (DR1, DR2, DR5), we show that shortly after RA treatement of mouse embryoid bodies or F9 cells, RARs occupy a large repertoire of DR0, DR2, DR5, DR8 and IR0 elements. In vitro, RAR-RXR bind these non-canonical spacings with comparable affinities to DR2 and DR5. Most DR8 elements comprise three half sites with DR2 and DR0 spacings. This specific half site organisation constitutes a previously unrecognised, but frequent signature of RAR binding elements and acts as an RARE. At later stages of embryoid body differentiation, RARs relocalise to a restricted repertoire of sites comprising predominantly DR5 elements. Differentiation thus involves genomic relocalisation of RARs, and a switch from DR0 and DR8 at early times to DR5 at later stages.
Project description:Retinoic Acid Receptors (RARs) bind RA-response elements in regulatory regions of their target genes. While canonical RAREs comprise direct repeats of the consensus 5’-RGKTCA-3’ sequence separated by 1, 2 or 5 nucleotides (DR1, DR2, DR5), we show that shortly after RA treatement of mouse embryoid bodies or F9 cells, RARs occupy a large repertoire of DR0, DR2, DR5, DR8 and IR0 elements. In vitro, RAR-RXR bind these non-canonical spacings with comparable affinities to DR2 and DR5. Most DR8 elements comprise three half sites with DR2 and DR0 spacings. This specific half site organisation constitutes a previously unrecognised, but frequent signature of RAR binding elements and acts as an RARE. At later stages of embryoid body differentiation, RARs relocalise to a restricted repertoire of sites comprising predominantly DR5 elements. Differentiation thus involves genomic relocalisation of RARs, and a switch from DR0 and DR8 at early times to DR5 at later stages. Examination of genomic localisation of RAR in differentiating embryoid bodies.
Project description:The assembly of fission yeast pericentromeric heterochromatin and generation of small interfering RNAs (siRNAs) from noncoding centromeric transcripts are mutually dependent processes. How this interdependent positive feedback loop is first triggered is a fundamental unanswered question. Here we show that two distinct Argonaute (Ago1)-dependent pathways mediate small RNA generation. RNA-dependent RNA polymerase complex (RDRC) and Dicer act on specific noncoding RNAs to generate siRNAs by a mechanism that requires the slicer activity of Ago1 but is independent of pre-existing heterochromatin. In the absence of RDRC or Dicer, a distinct class of small RNAs, called primal small RNAs (priRNAs), associate with Ago1. priRNAs are degradation products of abundant transcripts, which bind to Ago1 and target antisense transcripts that result from bidirectional transcription of DNA repeats. Our results suggest that a transcriptome surveillance mechanism based on the random association of RNA degradation products with Argonaute triggers siRNA amplification and heterochromatin assembly within DNA repeats. small RNA profiling in wild type S. pombe cells and in 12 mutant cells