Transcription of laminin γ1 chain gene in rat mesangial cells: constitutive and inducible RNA polymerase II recruitment and chromatin states

2008 ◽  
Vol 294 (3) ◽  
pp. F525-F533 ◽  
Author(s):  
Joel D. Nelson ◽  
Steve Flanagin ◽  
Yasunobu Kawata ◽  
Oleg Denisenko ◽  
Karol Bomsztyk

The laminin γ1 chain, a critical component of the extracellular matrix, is encoded by the 125-kb-long Lamc1 locus. We profiled RNA polymerase II (Pol II) and histone modifications along the Lamc1 locus to explore transcription of this gene in its native chromatin environment. Treatment with 12-O-tetradecanoylphorbol-13-acetate increased Lamc1 mRNA in rat mesangial cells (RMC). This increase was matched by an increase in Pol II density along the entire length of the Lamc1 locus. In contrast, in the hepatocarcinoma cell line (HTC-IR) an increase in Pol II density was restricted to the promoter and was not followed by mRNA induction. The pattern of histone H3 methylation was similar for both cell types but an increase in H3 lysine 9 acetylation observed at the 5′-end was weaker in HTC-IR cells than in RMC. All of the histone modifications showed spatial patterns where levels differed greatly between the 5′- and 3′-ends of Lamc1. Conversely, at the short, highly induced egr-1 gene the differences in chromatin marks between the 5′- and 3′-ends were much smaller. The results of this study suggest that 1) Lamc1 transcription can be controlled after transcription initiation, to our knowledge, the first time this has been shown in an extracellular matrix gene, and 2) the length of a gene is a factor that can affect the chromatin environment for Pol II elongation.

2020 ◽  
Vol 36 (1) ◽  
pp. 1-34 ◽  
Author(s):  
Sara Osman ◽  
Patrick Cramer

Gene transcription by RNA polymerase II (Pol II) is the first step in the expression of the eukaryotic genome and a focal point for cellular regulation during development, differentiation, and responses to the environment. Two decades after the determination of the structure of Pol II, the mechanisms of transcription have been elucidated with studies of Pol II complexes with nucleic acids and associated proteins. Here we provide an overview of the nearly 200 available Pol II complex structures and summarize how these structures have elucidated promoter-dependent transcription initiation, promoter-proximal pausing and release of Pol II into active elongation, and the mechanisms that Pol II uses to navigate obstacles such as nucleosomes and DNA lesions. We predict that future studies will focus on how Pol II transcription is interconnected with chromatin transitions, RNA processing, and DNA repair.


2008 ◽  
Vol 28 (12) ◽  
pp. 3979-3994 ◽  
Author(s):  
Lu Gao ◽  
David S. Gross

ABSTRACT It is well accepted that for transcriptional silencing in budding yeast, the evolutionarily conserved lysine deacetylase Sir2, in concert with its partner proteins Sir3 and Sir4, establishes a chromatin structure that prevents RNA polymerase II (Pol II) transcription. However, the mechanism of repression remains controversial. Here, we show that the recruitment of Pol II, as well as that of the general initiation factors TBP and TFIIH, occurs unimpeded to the silent HMR a 1 and HMLα1/HMLα2 mating promoters. This, together with the fact that Pol II is Ser5 phosphorylated, implies that SIR-mediated silencing is permissive to both preinitiation complex (PIC) assembly and transcription initiation. In contrast, the occupancy of factors critical to both mRNA capping and Pol II elongation, including Cet1, Abd1, Spt5, Paf1C, and TFIIS, is virtually abolished. In agreement with this, efficiency of silencing correlates not with a restriction in Pol II promoter occupancy but with a restriction in capping enzyme recruitment. These observations pinpoint the transition between polymerase initiation and elongation as the step targeted by Sir2 and indicate that transcriptional silencing is achieved through the differential accessibility of initiation and capping/elongation factors to chromatin. We compare Sir2-mediated transcriptional silencing to a second repression mechanism, mediated by Tup1. In contrast to Sir2, Tup1 prevents TBP, Pol II, and TFIIH recruitment to the HMLα1 promoter, thereby abrogating PIC formation.


2004 ◽  
Vol 24 (7) ◽  
pp. 2863-2874 ◽  
Author(s):  
Thomas C. Tubon ◽  
William P. Tansey ◽  
Winship Herr

ABSTRACT The general transcription factor TFIIB is a highly conserved and essential component of the eukaryotic RNA polymerase II (pol II) transcription initiation machinery. It consists of a single polypeptide with two conserved structural domains: an amino-terminal zinc ribbon structure (TFIIBZR) and a carboxy-terminal core (TFIIBCORE). We have analyzed the role of the amino-terminal region of human TFIIB in transcription in vivo and in vitro. We identified a small nonconserved surface of the TFIIBZR that is required for pol II transcription in vivo and for different types of basal pol II transcription in vitro. Consistent with a general role in transcription, this TFIIBZR surface is directly involved in the recruitment of pol II to a TATA box-containing promoter. Curiously, although the amino-terminal human TFIIBZR domain can recruit both human pol II and yeast (Saccharomyces cerevisiae) pol II, the yeast TFIIB amino-terminal region recruits yeast pol II but not human pol II. Thus, a critical process in transcription from many different promoters—pol II recruitment—has changed in sequence specificity during eukaryotic evolution.


2007 ◽  
Vol 27 (6) ◽  
pp. 2059-2073 ◽  
Author(s):  
Victoria H. Cowling ◽  
Michael D. Cole

ABSTRACT Myc is a transcription factor which is dependent on its DNA binding domain for transcriptional regulation of target genes. Here, we report the surprising finding that Myc mutants devoid of direct DNA binding activity and Myc target gene regulation can rescue a substantial fraction of the growth defect in myc −/− fibroblasts. Expression of the Myc transactivation domain alone induces a transcription-independent elevation of the RNA polymerase II (Pol II) C-terminal domain (CTD) kinases cyclin-dependent kinase 7 (CDK7) and CDK9 and a global increase in CTD phosphorylation. The Myc transactivation domain binds to the transcription initiation sites of these promoters and stimulates TFIIH binding in an MBII-dependent manner. Expression of the Myc transactivation domain increases CDK mRNA cap methylation, polysome loading, and the rate of translation. We find that some traditional Myc transcriptional target genes are also regulated by this Myc-driven translation mechanism. We propose that Myc transactivation domain-driven RNA Pol II CTD phosphorylation has broad effects on both transcription and mRNA metabolism.


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.


2018 ◽  
Author(s):  
M. Boehning ◽  
C. Dugast-Darzacq ◽  
M. Rankovic ◽  
A. S. Hansen ◽  
T. Yu ◽  
...  

The carboxy-terminal domain (CTD) of RNA polymerase (Pol) II is an intrinsically disordered low-complexity region that is critical for pre-mRNA transcription and processing. The CTD consists of hepta-amino acid repeats varying in number from 52 in humans to 26 in yeast. Here we report that human and yeast CTDs undergo cooperative liquid phase separation at increasing protein concentration, with the shorter yeast CTD forming less stable droplets. In human cells, truncation of the CTD to the length of the yeast CTD decreases Pol II clustering and chromatin association whereas CTD extension has the opposite effect. CTD droplets can incorporate intact Pol II and are dissolved by CTD phosphorylation with the transcription initiation factor IIH kinase CDK7. Together with published data, our results suggest that Pol II forms clusters/hubs at active genes through interactions between CTDs and with activators, and that CTD phosphorylation liberates Pol II enzymes from hubs for promoter escape and transcription elongation.


2004 ◽  
Vol 24 (4) ◽  
pp. 1709-1720 ◽  
Author(s):  
P. Geetha Rani ◽  
Jeffrey A. Ranish ◽  
Steven Hahn

ABSTRACT Protein purification and depletion studies were used to determine the major stable forms of RNA polymerase II (Pol II) complexes found in Saccharomyces cerevisiae nuclear extracts. About 50% of Pol II is found associated with the general transcription factor TFIIF (Pol II-TFIIF), and about 20% of Pol II is associated with Mediator (Pol-Med). No Pol II-Med-TFIIF complex was observed. The activity of Pol II and the purified Pol II complexes in transcription initiation and reinitiation was investigated by supplementing extracts depleted of either total Pol II or total TFIIF with purified Pol II or the Pol II complexes. We found that all three forms of Pol II can complement Pol II-depleted extracts for transcription initiation, but Pol II-TFIIF has the highest specific activity. Similarly, Pol II-TFIIF has a much higher specific activity than TFIIF for complementation of TFIIF transcription activity. Although the Pol II-TFIIF and Pol II-Med complexes were stable when purified, we found these complexes were dynamic in extracts under transcription conditions, with a single polymerase capable of exchanging bound Mediator and TFIIF. Using a purified system to examine transcription reinitiation, we found that Pol II-TFIIF was active in promoting multiple rounds of transcription while Pol II-Med was nearly inactive. These results suggest that both the Pol II-Med and Pol II-TFIIF complexes can be recruited for transcription initiation but that only the Pol II-TFIIF complex is competent for transcription reinitiation.


1993 ◽  
Vol 13 (10) ◽  
pp. 6403-6415 ◽  
Author(s):  
S Connelly ◽  
W Filipowicz

Formation of the 3' ends of RNA polymerase II (Pol II)-specific U small nuclear RNAs (U snRNAs) in vertebrate cells is dependent upon transcription initiation from the U snRNA gene promoter. Moreover, U snRNA promoters are unable to direct the synthesis of functional polyadenylated mRNAs. In this work, we have investigated whether U snRNA 3'-end formation and transcription initiation are also coupled in plants. We have first characterized the requirements for 3'-end formation of an Arabidopsis U2 snRNA expressed in transfected protoplasts of Nicotiana plumbaginifolia. We found that the 3'-end-adjacent sequence CA (N)3-10AGTNNAA, conserved in plant Pol II-specific U snRNA genes, is essential for the 3'-end formation of U2 transcripts and, similar to the vertebrate 3' box, is highly tolerant to mutation. The 3'-flanking regions of an Arabidopsis U5 and a maize U2 snRNA gene can effectively substitute for the Arabidopsis U2 3'-end formation signal, indicating that these signals are functionally equivalent among different Pol II-transcribed snRNA genes. The plant U snRNA 3'-end formation signal can be recognized irrespective of whether transcription initiation occurs at U snRNA or mRNA gene promoters, although efficiency of 3' box utilization is higher when transcription initiation occurs at the U snRNA promoter. Moreover, transcripts initiated from the U2 gene promoter can be spliced and polyadenylated. Transcription from a Pol III-specific plant U snRNA gene promoter is not compatible with polyadenylation. Finally, we reveal that initiation at a Pol II-specific plant U snRNA gene promoter can occur in the absence of the snRNA coding region and a functional snRNA 3'-end formation signal, demonstrating that these sequences play no role in determining the RNA polymerase specificity of plant U snRNA genes.


2016 ◽  
Vol 36 (13) ◽  
pp. 1856-1867 ◽  
Author(s):  
Jianxun Feng ◽  
Haiyun Gan ◽  
Matthew L. Eaton ◽  
Hui Zhou ◽  
Shuqi Li ◽  
...  

FACT (facilitateschromatintranscription) consists of two essential subunits, Spt16 and Pob3, and functions as a histone chaperone. Mutation ofspt16results in a global loss of nucleosomes as well as aberrant transcription. Here, we show that the majority of nucleosome changes upon Spt16 depletion are alterations in nucleosome fuzziness and position shift. Most nucleosomal changes are suppressed by the inhibition of RNA polymerase II (Pol II) activity. Surprisingly, a small subgroup of nucleosome changes is resistant to transcriptional inhibition. Notably, Spt16 and distinct histone modifications are enriched at this subgroup of nucleosomes. We also report 1,037Spt16-suppressednoncodingtranscripts (SNTs) and found that the SNT start sites are enriched with the subgroup of nucleosomes resistant to Pol II inhibition. Finally, the nucleosomes at genes overlapping SNTs are more susceptible to changes upon Spt16 depletion than those without SNTs. Taken together, our results support a model in which Spt16 has a role in maintaining local nucleosome stability to inhibit initiation of SNT transcription, which once initiated drives additional nucleosome loss upon Spt16 depletion.


2001 ◽  
Vol 21 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Seiji Yamamoto ◽  
Yoshinori Watanabe ◽  
Peter J. van der Spek ◽  
Tomomichi Watanabe ◽  
Hiroyuki Fujimoto ◽  
...  

ABSTRACT The general transcription factor TFIIE plays important roles in transcription initiation and in the transition to elongation. However, little is known about its function during these steps. Here we demonstrate for the first time that TFIIH-mediated phosphorylation of RNA polymerase II (Pol II) is essential for the transition to elongation. This phosphorylation occurs at serine position 5 (Ser-5) of the carboxy-terminal domain (CTD) heptapeptide sequence of the largest subunit of Pol II. In a human in vitro transcription system with a supercoiled template, this process was studied using a human TFIIE (hTFIIE) homolog from Caenorhabditis elegans (ceTFIIEα and ceTFIIEβ). ceTFIIEβ could partially replace hTFIIEβ, whereas ceTFIIEα could not replace hTFIIEα. We present the studies of TFIIE binding to general transcription factors and the effects of subunit substitution on CTD phosphorylation. As a result, ceTFIIEα did not bind tightly to hTFIIEβ, and ceTFIIEβ showed a similar profile for binding to its human counterpart and supported an intermediate level of CTD phosphorylation. Using antibodies against phosphorylated serine at either Ser-2 or Ser-5 of the CTD, we found that ceTFIIEβ induced Ser-5 phosphorylation very little but induced Ser-2 phosphorylation normally, in contrast to wild-type hTFIIE, which induced phosphorylation at both Ser-2 and Ser-5. In transcription transition assays using a linear template, ceTFIIEβ was markedly defective in its ability to support the transition to elongation. These observations provide evidence of TFIIE involvement in the transition and suggest that Ser-5 phosphorylation is essential for Pol II to be in the processive elongation form.


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