scholarly journals Repression of basal transcription by HMG2 is counteracted by TFIIH-associated factors in an ATP-dependent process.

1994 ◽  
Vol 14 (7) ◽  
pp. 4712-4721 ◽  
Author(s):  
G Stelzer ◽  
A Goppelt ◽  
F Lottspeich ◽  
M Meisterernst
Keyword(s):  
Rna Polymerase Ii ◽  
Chromosomal Protein ◽  
Hmg Proteins ◽  
Basal Transcription ◽  
Phosphodiester Bond ◽  
Promoter Complex ◽  
Atp Analogs ◽  
Gamma S ◽  
Nonhistone Chromosomal Protein

A basal repressor of class II gene transcription was identified, purified, and found to be identical to nonhistone chromosomal protein HMG2. HMG2 was shown to inhibit basal transcription under conditions in which transcription templates form soluble complexes with HMG2. Order-of-addition experiments clearly revealed that HMG2 acted after assembly of a TBP-TFIIA-promoter complex and before formation of the fourth phosphodiester bond by RNA polymerase II. Subsequently, an activity that efficiently counteracted repression of transcription by HMG2 in both TBP- and TFIID-containing transcription systems was isolated. Several lines of evidence suggested that antirepression was mediated by a TFIIH-associated factor. The antirepressor first coeluted with TFIIH, was depleted from this fraction by antibodies directed against the TFIIH subunit p62, was dependent on either ATP or dATP, and then was inhibited by the ATP analogs AMP-PNP and ATP gamma S. Relief of HMG2-mediated repression as well as basal promoter function of TFIIH may involve a helicase that coelutes with TFIIH and displays similar nucleotide specificities. Taken together, these data suggest novel consequences of chromatin-associated HMG proteins and they provide direct evidence for a role of TFIIH-associated enzymes in ATP-dependent antirepression of nonhistone chromosomal proteins.

Chromatin Structure and Gene Activity: The Role of Nonhistone Chromosomal Protein

1982 ◽  
Vol 13 (1) ◽  
pp. 1-86 ◽  
Author(s):  
Iain L. Cartwright ◽  
Susan M. Abmayr ◽  
Gerhard Fleischmann ◽  
Ky Lowenhaupt ◽  
Sarah C. R. Elgin ◽  
...  
Keyword(s):  
Chromatin Structure ◽  
Gene Activity ◽  
Chromosomal Protein ◽  
Nonhistone Chromosomal Protein

scholarly journals The role of ATP in in vitro vaccinia virus RNA synthesis effects of AMP-PNP and ATP gamma S.

1980 ◽  
Vol 255 (11) ◽  
pp. 5396-5403
Author(s):  
S. Shuman ◽  
E. Spencer ◽  
H. Furneaux ◽  
J. Hurwitz
Keyword(s):  
Vaccinia Virus ◽  
Rna Synthesis ◽  
Virus Rna ◽  
Gamma S

scholarly journals Cell cycle-dependent regulation of RNA polymerase II basal transcription activity

1995 ◽  
Vol 23 (20) ◽  
pp. 4050-4054 ◽  
Author(s):  
Masatomo Yonaha ◽  
Taku Chibazakura ◽  
Shigetaka Kitajima ◽  
Yukio Yasukochi
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Basal Transcription ◽  
Transcription Activity ◽  
Cycle Dependent

scholarly journals Loss of Ubp3 increases silencing, decreases unequal recombination in rDNA, and shortens the replicative life span in Saccharomyces cerevisiae

2014 ◽  
Vol 25 (12) ◽  
pp. 1916-1924 ◽  
Author(s):  
David Öling ◽  
Rehan Masoom ◽  
Kristian Kvint
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Life Span ◽  
Rna Polymerase Ii ◽  
Ribosomal Dna ◽  
Genetic Evidence ◽  
Wild Type ◽  
Replicative Life Span ◽  
Unequal Recombination

Ubp3 is a conserved ubiquitin protease that acts as an antisilencing factor in MAT and telomeric regions. Here we show that ubp3∆ mutants also display increased silencing in ribosomal DNA (rDNA). Consistent with this, RNA polymerase II occupancy is lower in cells lacking Ubp3 than in wild-type cells in all heterochromatic regions. Moreover, in a ubp3∆ mutant, unequal recombination in rDNA is highly suppressed. We present genetic evidence that this effect on rDNA recombination, but not silencing, is entirely dependent on the silencing factor Sir2. Further, ubp3∆ sir2∆ mutants age prematurely at the same rate as sir2∆ mutants. Thus our data suggest that recombination negatively influences replicative life span more so than silencing. However, in ubp3∆ mutants, recombination is not a prerequisite for aging, since cells lacking Ubp3 have a shorter life span than isogenic wild-type cells. We discuss the data in view of different models on how silencing and unequal recombination affect replicative life span and the role of Ubp3 in these processes.

Facultative heterochromatization in parahaploid male mealybugs: involvement of a heterochromatin-associated protein

Development ◽  
2001 ◽  
Vol 128 (19) ◽  
pp. 3809-3817 ◽  
Author(s):  
Silvia Bongiorni ◽  
Milena Mazzuoli ◽  
Stefania Masci ◽  
Giorgio Prantera
Keyword(s):  
Monoclonal Antibody ◽  
Drosophila Melanogaster ◽  
Constitutive Heterochromatin ◽  
Planococcus Citri ◽  
Chromosomal Protein ◽  
Paternal Chromosome ◽  
Localization Pattern ◽  
Males And Females ◽  
Male Specific ◽  
Nonhistone Chromosomal Protein

The behavior of chromosomes during development of the mealybug Planococcus citri provides one of the most dramatic examples of facultative heterochromatization. In male embryos, the entire haploid paternal chromosome set becomes heterochromatic at mid-cleavage. Male mealybugs are thus functionally haploid, owing to heterochromatization (parahaploidy). To understand the mechanisms underlying facultative heterochromatization in male mealybugs, we have investigated the possible involvement of an HP-1-like protein in this process. HP-1 is a conserved, nonhistone chromosomal protein with a proposed role in heterochromatinization in other species. It was first identified in Drosophila melanogaster as a protein enriched in the constitutive heterochromatin of polytene chromosome. Using a monoclonal antibody raised against the Drosophila HP-1 in immunoblot and immunocytological experiments, we provide evidence for the presence of an HP-1-like in Planococcus citri males and females. In males, the HP-1-like protein is preferentially associated with the male-specific heterochromatin. In the developing male embryos, its appearance precedes the onset of heterochromatization. In females, the HP-1-like protein displays a scattered but reproducible localization pattern along chromosomes. The results indicate a role for an HP-1-like protein in the facultative heterochromatization process.

scholarly journals Cryptic Transcription and Early Termination in the Control of Gene Expression

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Jessie Colin ◽  
Domenico Libri ◽  
Odil Porrua
Keyword(s):  
Gene Expression ◽  
Rna Polymerase Ii ◽  
Regulatory Function ◽  
Large Set ◽  
Control Of Gene Expression ◽  
Alternative Transcription ◽  
Cryptic Transcription ◽  
Nuclear Exosome ◽  
The Impact

Recent studies on yeast transcriptome have revealed the presence of a large set of RNA polymerase II transcripts mapping to intergenic and antisense regions or overlapping canonical genes. Most of these ncRNAs (ncRNAs) are subject to termination by the Nrd1-dependent pathway and rapid degradation by the nuclear exosome and have been dubbed cryptic unstable transcripts (CUTs). CUTs are often considered as by-products of transcriptional noise, but in an increasing number of cases they play a central role in the control of gene expression. Regulatory mechanisms involving expression of a CUT are diverse and include attenuation, transcriptional interference, and alternative transcription start site choice. This review focuses on the impact of cryptic transcription on gene expression, describes the role of the Nrd1-complex as the main actor in preventing nonfunctional and potentially harmful transcription, and details a few systems where expression of a CUT has an essential regulatory function. We also summarize the most recent studies concerning other types of ncRNAs and their possible role in regulation.

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