scholarly journals NELF and GAGA Factor Are Linked to Promoter-Proximal Pausing at Many Genes in Drosophila

2008 ◽  
Vol 28 (10) ◽  
pp. 3290-3300 ◽  
Author(s):  
Chanhyo Lee ◽  
Xiaoyong Li ◽  
Aaron Hechmer ◽  
Michael Eisen ◽  
Mark D. Biggin ◽  
...  

ABSTRACT Recent analyses of RNA polymerase II (Pol II) revealed that Pol II is concentrated at the promoters of many active and inactive genes. NELF causes Pol II to pause in the promoter-proximal region of the hsp70 gene in Drosophila melanogaster. In this study, genome-wide location analysis (chromatin immunoprecipitation-microarray chip [ChIP-chip] analysis) revealed that NELF is concentrated at the 5′ ends of 2,111 genes in Drosophila cells. Permanganate genomic footprinting was used to determine if paused Pol II colocalized with NELF. Forty-six of 56 genes with NELF were found to have paused Pol II. Pol II pauses 30 to 50 nucleotides downstream from transcription start sites. Analysis of DNA sequences in the vicinity of paused Pol II identified a conserved DNA sequence that probably associates with TFIID but detected no evidence of RNA secondary structures or other conserved sequences that might directly control elongation. ChIP-chip experiments indicate that GAGA factor associates with 39% of the genes that have NELF. Surprisingly, NELF associates with almost one-half of the most highly expressed genes, indicating that NELF is not necessarily a repressor of gene expression. NELF-associated pausing of Pol II might be an obligatory but sometimes transient checkpoint during the transcription cycle.

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
William S Kruesi ◽  
Leighton J Core ◽  
Colin T Waters ◽  
John T Lis ◽  
Barbara J Meyer

The X-chromosome gene regulatory process called dosage compensation ensures that males (1X) and females (2X) express equal levels of X-chromosome transcripts. The mechanism in Caenorhabditis elegans has been elusive due to improperly annotated transcription start sites (TSSs). Here we define TSSs and the distribution of transcriptionally engaged RNA polymerase II (Pol II) genome-wide in wild-type and dosage-compensation-defective animals to dissect this regulatory mechanism. Our TSS-mapping strategy integrates GRO-seq, which tracks nascent transcription, with a new derivative of this method, called GRO-cap, which recovers nascent RNAs with 5′ caps prior to their removal by co-transcriptional processing. Our analyses reveal that promoter-proximal pausing is rare, unlike in other metazoans, and promoters are unexpectedly far upstream from the 5′ ends of mature mRNAs. We find that C. elegans equalizes X-chromosome expression between the sexes, to a level equivalent to autosomes, by reducing Pol II recruitment to promoters of hermaphrodite X-linked genes using a chromosome-restructuring condensin complex.


Author(s):  
Priyanka Barman ◽  
Rwik Sen ◽  
Amala Kaja ◽  
Jannatul Ferdoush ◽  
Shalini Guha ◽  
...  

San1 ubiquitin ligase is involved in nuclear protein quality control via its interaction with intrinsically disordered proteins for ubiquitylation and proteasomal degradation. Since several transcription/chromatin regulatory factors contain intrinsically disordered domains and can be inhibitory to transcription when in excess, San1 might be involved in transcription regulation. To address this, we analyzed the role of San1 in genome-wide association of TBP [that nucleates pre-initiation complex (PIC) formation for transcription initiation] and RNA polymerase II (Pol II). Our results reveal the roles of San1 in regulating TBP recruitment to the promoters and Pol II association with the coding sequences, and hence PIC formation and coordination of elongating Pol II, respectively. Consistently, transcription is altered in the absence of San1. Such transcriptional alteration is associated with impaired ubiquitylation and proteasomal degradation of Spt16 and gene association of Paf1, but not the incorporation of centromeric histone, Cse4, into the active genes in Δsan1 . Collectively, our results demonstrate distinct functions of a nuclear protein quality control factor in regulating the genome-wide PIC formation and elongating Pol II (and hence transcription), thus unraveling new gene regulatory mechanisms.


2007 ◽  
Vol 27 (5) ◽  
pp. 1631-1648 ◽  
Author(s):  
Igor Chernukhin ◽  
Shaharum Shamsuddin ◽  
Sung Yun Kang ◽  
Rosita Bergström ◽  
Yoo-Wook Kwon ◽  
...  

ABSTRACT CTCF is a transcription factor with highly versatile functions ranging from gene activation and repression to the regulation of insulator function and imprinting. Although many of these functions rely on CTCF-DNA interactions, it is an emerging realization that CTCF-dependent molecular processes involve CTCF interactions with other proteins. In this study, we report the association of a subpopulation of CTCF with the RNA polymerase II (Pol II) protein complex. We identified the largest subunit of Pol II (LS Pol II) as a protein significantly colocalizing with CTCF in the nucleus and specifically interacting with CTCF in vivo and in vitro. The role of CTCF as a link between DNA and LS Pol II has been reinforced by the observation that the association of LS Pol II with CTCF target sites in vivo depends on intact CTCF binding sequences. “Serial” chromatin immunoprecipitation (ChIP) analysis revealed that both CTCF and LS Pol II were present at the β-globin insulator in proliferating HD3 cells but not in differentiated globin synthesizing HD3 cells. Further, a single wild-type CTCF target site (N-Myc-CTCF), but not the mutant site deficient for CTCF binding, was sufficient to activate the transcription from the promoterless reporter gene in stably transfected cells. Finally, a ChIP-on-ChIP hybridization assay using microarrays of a library of CTCF target sites revealed that many intergenic CTCF target sequences interacted with both CTCF and LS Pol II. We discuss the possible implications of our observations with respect to plausible mechanisms of transcriptional regulation via a CTCF-mediated direct link of LS Pol II to the DNA.


2020 ◽  
Vol 117 (33) ◽  
pp. 19888-19895
Author(s):  
Haolin Liu ◽  
Srinivas Ramachandran ◽  
Nova Fong ◽  
Tzu Phang ◽  
Schuyler Lee ◽  
...  

More than 30% of genes in higher eukaryotes are regulated by RNA polymerase II (Pol II) promoter proximal pausing. Pausing is released by the positive transcription elongation factor complex (P-TEFb). However, the exact mechanism by which this occurs and whether phosphorylation of the carboxyl-terminal domain of Pol II is involved in the process remains unknown. We previously reported that JMJD5 could generate tailless nucleosomes at position +1 from transcription start sites (TSS), thus perhaps enable progression of Pol II. Here we find that knockout of JMJD5 leads to accumulation of nucleosomes at position +1. Absence of JMJD5 also results in loss of or lowered transcription of a large number of genes. Interestingly, we found that phosphorylation, by CDK9, of Ser2 within two neighboring heptad repeats in the carboxyl-terminal domain of Pol II, together with phosphorylation of Ser5 within the second repeat, HR-Ser2p (1, 2)-Ser5p (2) for short, allows Pol II to bind JMJD5 via engagement of the N-terminal domain of JMJD5. We suggest that these events bring JMJD5 near the nucleosome at position +1, thus allowing JMJD5 to clip histones on this nucleosome, a phenomenon that may contribute to release of Pol II pausing.


2020 ◽  
Vol 295 (12) ◽  
pp. 3990-4000 ◽  
Author(s):  
Sandeep Singh ◽  
Karol Szlachta ◽  
Arkadi Manukyan ◽  
Heather M. Raimer ◽  
Manikarna Dinda ◽  
...  

DNA double-stranded breaks (DSBs) are strongly associated with active transcription, and promoter-proximal pausing of RNA polymerase II (Pol II) is a critical step in transcriptional regulation. Mapping the distribution of DSBs along actively expressed genes and identifying the location of DSBs relative to pausing sites can provide mechanistic insights into transcriptional regulation. Using genome-wide DNA break mapping/sequencing techniques at single-nucleotide resolution in human cells, we found that DSBs are preferentially located around transcription start sites of highly transcribed and paused genes and that Pol II promoter-proximal pausing sites are enriched in DSBs. We observed that DSB frequency at pausing sites increases as the strength of pausing increases, regardless of whether the pausing sites are near or far from annotated transcription start sites. Inhibition of topoisomerase I and II by camptothecin and etoposide treatment, respectively, increased DSBs at the pausing sites as the concentrations of drugs increased, demonstrating the involvement of topoisomerases in DSB generation at the pausing sites. DNA breaks generated by topoisomerases are short-lived because of the religation activity of these enzymes, which these drugs inhibit; therefore, the observation of increased DSBs with increasing drug doses at pausing sites indicated active recruitment of topoisomerases to these sites. Furthermore, the enrichment and locations of DSBs at pausing sites were shared among different cell types, suggesting that Pol II promoter-proximal pausing is a common regulatory mechanism. Our findings support a model in which topoisomerases participate in Pol II promoter-proximal pausing and indicated that DSBs at pausing sites contribute to transcriptional activation.


2003 ◽  
Vol 23 (6) ◽  
pp. 1961-1967 ◽  
Author(s):  
Chonghui Cheng ◽  
Phillip A. Sharp

ABSTRACT The carboxyl-terminal domain (CTD) of RNA polymerase II (Pol II) can be phosphorylated at serine 2 (Ser-2) and serine 5 (Ser-5) of the CTD heptad repeat YSPTSPS, and this phosphorylation is important in coupling transcription to RNA processing, including 5′ capping, splicing, and polyadenylation. The mammalian endogenous dihydrofolate reductase and γ-actin genes have been used to study the association of Pol II with different regions of transcribed genes (promoter-proximal compared to distal regions) and the phosphorylation status of its CTD. For both genes, Pol II is more concentrated in the promoter-proximal regions than in the interior regions. Moreover, different phosphorylation forms of Pol II are associated with distinct regions. Ser-5 phosphorylation of Pol II is concentrated near the promoter, while Ser-2 phosphorylation is observed throughout the gene. These results suggest that the accumulation of paused Pol II in promoter-proximal regions may be a common feature of gene regulation in mammalian cells.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Anand Ranjan ◽  
Vu Q Nguyen ◽  
Sheng Liu ◽  
Jan Wisniewski ◽  
Jee Min Kim ◽  
...  

The H2A.Z histone variant, a genome-wide hallmark of permissive chromatin, is enriched near transcription start sites in all eukaryotes. H2A.Z is deposited by the SWR1 chromatin remodeler and evicted by unclear mechanisms. We tracked H2A.Z in living yeast at single-molecule resolution, and found that H2A.Z eviction is dependent on RNA Polymerase II (Pol II) and the Kin28/Cdk7 kinase, which phosphorylates Serine 5 of heptapeptide repeats on the carboxy-terminal domain of the largest Pol II subunit Rpb1. These findings link H2A.Z eviction to transcription initiation, promoter escape and early elongation activities of Pol II. Because passage of Pol II through +1 nucleosomes genome-wide would obligate H2A.Z turnover, we propose that global transcription at yeast promoters is responsible for eviction of H2A.Z. Such usage of yeast Pol II suggests a general mechanism coupling eukaryotic transcription to erasure of the H2A.Z epigenetic signal.


2015 ◽  
Author(s):  
Jie Xiong ◽  
Shan Gao ◽  
Wen Dui ◽  
Wentao Yang ◽  
Xiao Chen ◽  
...  

The ciliate protozoan Tetrahymena thermophila contains two types of structurally and functionally differentiated nuclei: the transcriptionally active somatic macronucleus (MAC) and the transcriptionally silent germ-line micronucleus (MIC). Here we demonstrate that MAC features well-positioned nucleosomes downstream of transcription start sites (TSS) likely connected with promoter proximal pausing of RNA polymerase II, as well as in exonic regions flanking both the 5′ and 3′ splice sites. In contrast, nucleosomes in MIC are more delocalized. Nucleosome occupancy in MAC and MIC are nonetheless highly correlated with each other and with predictions based upon DNA sequence features. Arrays of well-positioned nucleosomes are often correlated with GC content oscillations, suggesting significant contributions from cis-determinants. We propose that cis- and trans-determinants may coordinately accommodate some well-positioned nucleosomes with important functions, driven by a process in which positioned nucleosomes shape the mutational landscape of associated DNA sequences, while the DNA sequences in turn reinforce nucleosome positioning.


2017 ◽  
Author(s):  
Anish Dattani ◽  
Damian Kao ◽  
Yuliana Mihaylova ◽  
Prasad Abnave ◽  
Samantha Hughes ◽  
...  

AbstractPlanarian flatworms have an indefinite capacity to regenerate missing or damaged body parts owing to a population of pluripotent adult stems cells called neoblasts (NBs). Currently, little is known about the importance of the epigenetic status of NBs and how histone modifications regulate homeostasis and cellular differentiation. We have developed an improved and optimized ChIP-seq protocol for NBs in Schmidtea mediterranea and have generated genome-wide profiles for the active marks H3K4me3 and H3K36me3, and suppressive marks H3K4me1 and H3K27me3. The genome-wide profiles of these marks were found to correlate well with NB gene expression profiles. We found that genes with little transcriptional activity in the NB compartment but which switch on in post-mitotic progeny during differentiation are bivalent, being marked by both H3K4me3 and H3K27me3 at promoter regions. In further support of this hypothesis bivalent genes also have a high level of paused RNA Polymerase II at the promoter-proximal region. Overall, this study confirms that epigenetic control is important for the maintenance of a NB transcriptional program and makes a case for bivalent promoters as a conserved feature of animal stem cells and not a vertebrate specific innovation. By establishing a robust ChIP-seq protocol and analysis methodology, we further promote planarians as a promising model system to investigate histone modification mediated regulation of stem cell function and differentiation.


2020 ◽  
Author(s):  
Miki Jishage ◽  
Keiichi Ito ◽  
Chi-Shuen Chu ◽  
Xiaoling Wang ◽  
Masashi Yamaji ◽  
...  

AbstractLiver regeneration and metabolism are highly interconnected. Here, we show that hepatocyte-specific ablation of RNA polymerase II (Pol II)-associated Gdown1 leads to down-regulation of highly expressed genes involved in plasma protein synthesis and metabolism, a concomitant cell cycle re-entry associated with induction of cell cycle-related genes (including cyclin D1). and up-regulation of p21 through activation of p53 signaling. In the absence of p53, Gdown1-deficient hepatocytes show a severe dysregulation of cell cycle progression, with incomplete mitoses, and a pre-malignant-like transformation. Mechanistically, Gdown1 is associated with elongating Pol II on the highly expressed genes and its ablation leads to reduced Pol II recruitment to these genes, suggesting that Pol II redistribution may facilitate hepatocyte re-entry into the cell cycle. These results establish an important physiological function for a Pol II regulatory factor (Gdown1) in the maintenance of normal liver cell transcription through constraints on cell cycle re-entry of quiescent hepatocytes.


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