A putative transcriptional elongation factor hIws1 is essential for mammalian cell proliferation

2007 ◽  
Vol 353 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Zhangguo Liu ◽  
Zhongwei Zhou ◽  
Guohong Chen ◽  
Shilai Bao
Keyword(s):  
Cell Proliferation ◽  
Mammalian Cell ◽  
Elongation Factor ◽  
Transcriptional Elongation

Downregulation of Dihydrotestosterone and Estradiol Levels by HEXIM1

Endocrinology ◽  
2021 ◽  
Vol 163 (1) ◽  
Author(s):  
Fitya Mozar ◽  
Vikas Sharma ◽  
Shashank Gorityala ◽  
Jeffrey M Albert ◽  
Yan Xu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Rna Polymerase Ii ◽  
Transcriptional Activity ◽  
Elongation Factor ◽  
Estrogen Receptor Α ◽  
Transcriptional Elongation ◽  
Key Enzyme ◽  
Functional Consequences ◽  
Inducible Protein

Abstract We have previously reported that hexamethylene bis-acetamide inducible protein 1 (HEXIM1) inhibits the activity of ligand-bound estrogen receptor α (ERα) and the androgen receptor (AR) by disrupting the interaction between these receptors and positive transcriptional elongation factor b (P-TEFb) and attenuating RNA polymerase II (RNAPII) phosphorylation at serine 2. Functional consequences of the inhibition of transcriptional activity of ERα and AR by HEXIM1 include the inhibition of ERα- and AR-dependent gene expression, respectively, and the resulting attenuation of breast cancer (BCa) and prostate cancer (PCa) cell proliferation and growth. In our present study, we determined that HEXIM1 inhibited AKR1C3 expression in BCa and PCa cells. AKR1C3, also known as 17β-hydroxysteroid dehydrogenase (17β-HSD) type 5, is a key enzyme involved in the synthesis of 17β-estradiol (E2) and 5-dihydrotestosterone (DHT). Downregulation of AKR1C3 by HEXIM1 influenced E2 and DHT production, estrogen- and androgen-dependent gene expression, and cell proliferation. Our studies indicate that HEXIM1 has the unique ability to inhibit both the transcriptional activity of the ER and AR and the synthesis of the endogenous ligands of these receptors.

scholarly journals Regulation of P-TEFb Elongation Complex Activity by CDK9 Acetylation

2007 ◽  
Vol 27 (13) ◽  
pp. 4641-4651 ◽  
Author(s):  
Junjiang Fu ◽  
Ho-Geun Yoon ◽  
Jun Qin ◽  
Jiemin Wong
Keyword(s):  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Transcriptional Elongation ◽  
Elongation Complex ◽  
Complex Activity ◽  
Interacting Protein ◽  
Pol Ii ◽  
Carboxy Terminal

ABSTRACT P-TEFb, comprised of CDK9 and a cyclin T subunit, is a global transcriptional elongation factor important for most RNA polymerase II (pol II) transcription. P-TEFb facilitates transcription elongation in part by phosphorylating Ser2 of the heptapeptide repeat of the carboxy-terminal domain (CTD) of the largest subunit of pol II. Previous studies have shown that P-TEFb is subjected to negative regulation by forming an inactive complex with 7SK small RNA and HEXIM1. In an effort to investigate the molecular mechanism by which corepressor N-CoR mediates transcription repression, we identified HEXIM1 as an N-CoR-interacting protein. This finding led us to test whether the P-TEFb complex is regulated by acetylation. We demonstrate that CDK9 is an acetylated protein in cells and can be acetylated by p300 in vitro. Through both in vitro and in vivo assays, we identified lysine 44 of CDK9 as a major acetylation site. We present evidence that CDK9 is regulated by N-CoR and its associated HDAC3 and that acetylation of CDK9 affects its ability to phosphorylate the CTD of pol II. These results suggest that acetylation of CDK9 is an important posttranslational modification that is involved in regulating P-TEFb transcriptional elongation function.

Bacterially produced inclusion bodies as biocompatible materials for substrate-dependent mammalian cell proliferation

2010 ◽  
Vol 150 ◽  
pp. 434-435
Author(s):  
J. Seras ◽  
C. Díez-Gil ◽  
E. Vazquez ◽  
S. Krabbenborg ◽  
E. Rodríguez-Carmona ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mammalian Cell ◽  
Inclusion Bodies ◽  
Biocompatible Materials

Identification of rpo30, a vaccinia virus RNA polymerase gene with structural similarity to a eucaryotic transcription elongation factor

1990 ◽  
Vol 10 (10) ◽  
pp. 5433-5441
Author(s):  
B Y Ahn ◽  
P D Gershon ◽  
E V Jones ◽  
B Moss
Keyword(s):  
Rna Polymerase ◽  
Vaccinia Virus ◽  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Viral Rna ◽  
In Vitro Translation ◽  
Virus Protein ◽  
Transcriptional Elongation

Eucaryotic transcription factors that stimulate RNA polymerase II by increasing the efficiency of elongation of specifically or randomly initiated RNA chains have been isolated and characterized. We have identified a 30-kilodalton (kDa) vaccinia virus-encoded protein with apparent homology to SII, a 34-kDa mammalian transcriptional elongation factor. In addition to amino acid sequence similarities, both proteins contain C-terminal putative zinc finger domains. Identification of the gene, rpo30, encoding the vaccinia virus protein was achieved by using antibody to the purified viral RNA polymerase for immunoprecipitation of the in vitro translation products of in vivo-synthesized early mRNA selected by hybridization to cloned DNA fragments of the viral genome. Western immunoblot analysis using antiserum made to the vaccinia rpo30 protein expressed in bacteria indicated that the 30-kDa protein remains associated with highly purified viral RNA polymerase. Thus, the vaccinia virus protein, unlike its eucaryotic homolog, is an integral RNA polymerase subunit rather than a readily separable transcription factor. Further studies showed that the expression of rpo30 is regulated by dual early and later promoters.

scholarly journals HDAC stimulates gene expression through BRD4 availability in response to IFN and in interferonopathies

2018 ◽  
Vol 215 (12) ◽  
pp. 3194-3212 ◽  
Author(s):  
Isabelle J. Marié ◽  
Hao-Ming Chang ◽  
David E. Levy
Keyword(s):  
Autoimmune Diseases ◽  
Histone Deacetylases ◽  
Elongation Factor ◽  
Positive Function ◽  
Transcriptional Elongation ◽  
Hdac Inhibition ◽  
Transcriptional Initiation ◽  
Inducible Promoters ◽  
The Common

In contrast to the common role of histone deacetylases (HDACs) for gene repression, HDAC activity provides a required positive function for IFN-stimulated gene (ISG) expression. Here, we show that HDAC1/2 as components of the Sin3A complex are required for ISG transcriptional elongation but not for recruitment of RNA polymerase or transcriptional initiation. Transcriptional arrest by HDAC inhibition coincides with failure to recruit the epigenetic reader Brd4 and elongation factor P-TEFb due to sequestration of Brd4 on hyperacetylated chromatin. Brd4 availability is regulated by an equilibrium cycle between opposed acetyltransferase and deacetylase activities that maintains a steady-state pool of free Brd4 available for recruitment to inducible promoters. An ISG expression signature is a hallmark of interferonopathies and other autoimmune diseases. Combined inhibition of HDAC1/2 and Brd4 resolved the aberrant ISG expression detected in cells derived from patients with two inherited interferonopathies, ISG15 and USP18 deficiencies, defining a novel therapeutic approach to ISG-associated autoimmune diseases.

Characterization of the gene encoding the human transcriptional elongation factor TFIIS

Gene ◽  
1994 ◽  
Vol 139 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Park HeungRok ◽  
KwangHee Baek ◽  
Jeon ChoonJu ◽  
Agarwal Kan ◽  
Yoo OokJoon
Keyword(s):  
Elongation Factor ◽  
Transcriptional Elongation ◽  
Gene Encoding

Role of Intracellular pH in Mammalian Cell Proliferation

1992 ◽  
Vol 2 (3-4) ◽  
pp. 159-179 ◽  
Author(s):  
R.J. Gillies ◽  
R. Martinez-Zaguilan ◽  
E.P. Peterson ◽  
R. Perona
Keyword(s):  
Cell Proliferation ◽  
Intracellular Ph ◽  
Mammalian Cell
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