Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation12 and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters
Project description:Eukaryotic genomes are extensively transcribed, but unfettered transcription alters gene expression and leads to genome damage by several means. Divergent transcription occurs at active enhancers and promoters, distinct classes of cis-regulatory elements critical for precise control of gene expression. A key step in RNA Polymerase II (Pol II) transcription is promoter-proximal pausing, which occurs bidirectionally ~25-60 nucleotides downstream of transcription start sites (TSS). Promoter-proximal pause release is gated by the positive transcription elongation factor b (P-TEFb)-7SK snRNA pathway; release from 7SK allows P-TEFb phosphorylation of Pol II and subsequent elongation. The 7SK small nuclear ribonucleoprotein (snRNP) is thought to reside in the nucleoplasm, but it has been suggested that 7SK could operate physically on chromatin. Notably, while enhancer transcription is one of the earliest steps of gene activation and some enhancer RNAs (eRNAs) participate in gene regulation, far less is known about the control of eRNA transcription. Here we show that 7SK inhibits enhancer transcription by modulating nucleosome position. 7SK occupies enhancers and super enhancers genome-wide, and 7SK is required to limit eRNA initiation and synthesis in a manner distinct from promoter pausing. Clustered elements at super enhancers uniquely require 7SK to prevent convergent transcription of colliding polymerases that lead to DNA damage. 7SK inhibits enhancer transcription by modulating chromatin structure, physically interacts with the BAF chromatin remodeling complex, and is required to recruit BAF to enhancers. In turn, 7SK occupancy at enhancers coincides with Brd4 and is exquisitely sensitive to the bromodomain inhibitor JQ1. Thus, 7SK employs distinct mechanisms to counteract diverse consequences of pervasive transcription that distinguish super enhancers, enhancers, and promoters.
Project description:Distal enhancers characterized by H3K4me1 mark play critical roles in developmental and transcriptional programs. However, potential roles of specific distal regulatory elements in regulating RNA Polymerase II (Pol II) promoter-proximal pause release remain poorly investigated. Here we report that a unique cohort of jumonji C domain-containing protein 6 (JMJD6) and bromodomain-containing protein 4 (Brd4) co-bound distal enhancers, termed anti-pause enhancers (A-PEs), regulate promoter-proximal pause release of a large subset of transcription units via long-range interactions. Brd4-dependent JMJD6 recruitment on A-PEs mediates erasure of H4R3me2(s), which is directly read by 7SK snRNA, and decapping/demethylation of 7SK snRNA, ensuring the dismissal of the 7SKsnRNA/HEXIM inhibitory complex. The interactions of both JMJD6 and Brd4 with the P-TEFb complex permit its activation and pause release of regulated coding genes. The functions of JMJD6/ Brd4-associated dual histone and RNA demethylase activity on anti-pause enhancers have intriguing implications for these proteins in development, homeostasis and disease. All Gro-seq(s) were designed to reveal the transcriptional targets of JMJD6 and Brd4, and assess the role of JMJD6 and Brd4 in Pol II promoter-proximal pause release. All ChIP-seq(s) were designed to understand the unique features, associated molecular mechanisms and functions of the anti-pause enhancers (A-PEs) discovered in the current study.