scholarly journals Bovine leukemia virus trans-activator p38tax activates heterologous promoters with a common sequence known as a cAMP-responsive element or the binding site of a cellular transcription factor ATF.

1989 ◽  
Vol 8 (2) ◽  
pp. 497-503 ◽  
Author(s):  
I. Katoh ◽  
Y. Yoshinaka ◽  
Y. Ikawa
Keyword(s):  
Transcription Factor ◽  
Binding Site ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
Cellular Transcription Factor ◽  
Responsive Element ◽  
Cellular Transcription ◽  
Common Sequence

scholarly journals Cellular Transcription Factor ZASC1 Regulates Murine Leukemia Virus Transcription

2010 ◽  
Vol 84 (15) ◽  
pp. 7473-7483 ◽  
Author(s):  
James W. Bruce ◽  
Michael Hierl ◽  
John A. T. Young ◽  
Paul Ahlquist
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Cell Line ◽  
Binding Sites ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Cellular Transcription Factor ◽  
Cellular Transcription ◽  
Ltr Promoter ◽  
Murine Leukemia

ABSTRACT To identify cellular processes involved in retroviral infection, we employed a high-volume forward genetic screen of insertionally mutagenized somatic cells using a murine leukemia virus (MLV) vector. This approach identified a clonal cell line that exhibited approximately 10-fold reduced gene expression from MLV vectors following infection despite supporting normal levels of MLV reverse transcription and integration. The defect in this cell line was specific for the MLV long terminal repeat (LTR) promoter, as normal levels of reporter gene expression were obtained from both an internal cytomegalovirus (CMV) promoter contained within an LTR-defective MLV vector and LTR expression from an avian sarcoma and leukosis virus (ASLV) vector. Complementation and shRNA knockdown experiments demonstrated that the defective gene in these cells is ZASC1 (ZNF639), a transcription factor with strong links to cancer and inherited ataxias. We demonstrated that ZASC1 is a sequence-specific DNA binding protein with three closely related binding sites located within the MLV LTR promoter, but it does not bind to the ASLV promoter. Mutating these putative ZASC1 binding sites significantly reduced levels of MLV gene expression. While wild-type ZASC1 activated expression from the MLV promoter, a green fluorescent protein-ZASC1 fusion protein showed dominant-negative inhibition of MLV gene expression. These studies identify the cellular transcription factor ZASC1 as an activator of MLV gene expression and provide tools that should be useful in studying the links between ZASC1 and human diseases.

scholarly journals trans-dominant mutants of E1A provide genetic evidence that the zinc finger of the trans-activating domain binds a transcription factor.

1991 ◽  
Vol 11 (9) ◽  
pp. 4287-4296 ◽  
Author(s):  
L C Webster ◽  
R P Ricciardi
Keyword(s):  
Transcription Factor ◽  
Zinc Finger ◽  
Cellular Protein ◽  
Site Directed Mutagenesis ◽  
Cellular Transcription Factor ◽  
Dominant Phenotype ◽  
Cellular Genes ◽  
Critical Residue ◽  
The Individual ◽  
Cellular Transcription

The 289R E1A protein of adenovirus stimulates transcription of early viral and certain cellular genes. trans-Activation requires residues 140 to 188, which encompass a zinc finger. Several studies have indicated that trans-activation by E1A is mediated through cellular transcription factors. In particular, the ability of the trans-dominant E1A point mutant hr5 (Ser-185 to Asn) to inhibit wild-type E1A trans-activation was proposed to result from the sequestration of a cellular factor. Using site-directed mutagenesis, we individually replaced every residue within and flanking the trans-activating domain with a conservative amino acid, revealing 16 critical residues. Six of the individual substitutions lying in a contiguous stretch C terminal to the zinc finger (carboxyl region183-188) imparted a trans-dominant phenotype. trans-Dominance was even produced by deletion of the entire carboxyl region183-188. Conversely, an intact finger region147-177 was absolutely required for trans-dominance, since second-site substitution of every critical residue in this region abrogated the trans-dominant phenotype of the hr5 protein. These data indicate that the finger region147-177 bind a limiting cellular transcription factor and that the carboxyl region183-188 provides a separate and essential function. In addition, we show that four negatively charged residues within the trans-activating domain do not comprise a distinct acidic activating region. We present a model in which the trans-activating domain of E1A binds to two different cellular protein targets through the finger and carboxyl regions.

scholarly journals Identification of an NF-kappa B binding site in the bovine leukemia virus promoter.

1995 ◽  
Vol 69 (10) ◽  
pp. 6005-6009 ◽  
Author(s):  
P A Brooks ◽  
J K Nyborg ◽  
G L Cockerell
Keyword(s):  
Binding Site ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
Nf Kappa B ◽  
Virus Promoter

trans-dominant mutants of E1A provide genetic evidence that the zinc finger of the trans-activating domain binds a transcription factor

1991 ◽  
Vol 11 (9) ◽  
pp. 4287-4296
Author(s):  
L C Webster ◽  
R P Ricciardi
Keyword(s):  
Transcription Factor ◽  
Zinc Finger ◽  
Cellular Protein ◽  
Site Directed Mutagenesis ◽  
Cellular Transcription Factor ◽  
Dominant Phenotype ◽  
Cellular Genes ◽  
Critical Residue ◽  
The Individual ◽  
Cellular Transcription

The 289R E1A protein of adenovirus stimulates transcription of early viral and certain cellular genes. trans-Activation requires residues 140 to 188, which encompass a zinc finger. Several studies have indicated that trans-activation by E1A is mediated through cellular transcription factors. In particular, the ability of the trans-dominant E1A point mutant hr5 (Ser-185 to Asn) to inhibit wild-type E1A trans-activation was proposed to result from the sequestration of a cellular factor. Using site-directed mutagenesis, we individually replaced every residue within and flanking the trans-activating domain with a conservative amino acid, revealing 16 critical residues. Six of the individual substitutions lying in a contiguous stretch C terminal to the zinc finger (carboxyl region183-188) imparted a trans-dominant phenotype. trans-Dominance was even produced by deletion of the entire carboxyl region183-188. Conversely, an intact finger region147-177 was absolutely required for trans-dominance, since second-site substitution of every critical residue in this region abrogated the trans-dominant phenotype of the hr5 protein. These data indicate that the finger region147-177 bind a limiting cellular transcription factor and that the carboxyl region183-188 provides a separate and essential function. In addition, we show that four negatively charged residues within the trans-activating domain do not comprise a distinct acidic activating region. We present a model in which the trans-activating domain of E1A binds to two different cellular protein targets through the finger and carboxyl regions.

scholarly journals Downregulation of vaccinia virus intermediate and late promoters by host transcription factor YY1

2009 ◽  
Vol 90 (7) ◽  
pp. 1592-1599 ◽  
Author(s):  
Bruce A. Knutson ◽  
Jaewook Oh ◽  
Steven S. Broyles
Keyword(s):  
Transcription Factor ◽  
Vaccinia Virus ◽  
Transcriptional Repression ◽  
Late Gene ◽  
Viral Promoter ◽  
Cellular Transcription Factor ◽  
Transcriptional Promoters ◽  
Transcription Factor Yy1 ◽  
Cellular Transcription

Approximately half of the intermediate and late gene transcriptional promoters of vaccinia virus have a binding site for the cellular transcription factor YY1 that overlaps the initiator elements. Depletion of YY1 using RNA interference enhanced the activity of these promoters, while overexpression of YY1 repressed their activity. Viral promoter nucleotide replacements that specifically impair the binding of YY1 mostly alleviated the transcriptional repression and correlated with the ability of YY1 to stably interact with the initiator DNAs in vitro. The transcriptional repression activity was localized to the C-terminal DNA-binding domain of the protein. These results indicate that YY1 functions to negatively regulate these vaccinia virus promoters by binding to their initiator elements.

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