scholarly journals Transcriptional activation by the adenovirus larger E1a product is mediated by members of the cellular transcription factor ATF family which can directly associate with E1a.

1993 ◽  
Vol 13 (1) ◽  
pp. 561-570 ◽  
Author(s):  
B Chatton ◽  
J L Bocco ◽  
M Gaire ◽  
C Hauss ◽  
B Reimund ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Metal Binding ◽  
Cdna Clones ◽  
Adenovirus E1a ◽  
Cellular Transcription Factor ◽  
Binding Domains ◽  
Mrna Gene ◽  
Conserved Region ◽  
Cellular Transcription

We recently isolated three cDNA clones encoding closely related proteins (ATFa1, ATFa2, and ATFa3) that belong to the activating transcription factor-cyclic AMP-responsive element family of cellular transcription factors. Using cotransfection experiments, we showed that these proteins mediate the transcriptional activation induced by the adenovirus E1a 13S mRNA gene product and that the zinc-binding domains present in both E1a conserved region 3 and the most N-terminal portion of the ATFa proteins play crucial roles in this activity. Reciprocal coimmunoprecipitation experiments demonstrated direct interactions between these proteins. Neither the conserved region 3 domain of E1a nor the N-terminal metal-binding element of ATFa is essential for these interactions. The simultaneous alteration of both the N-terminal and the C-terminal domains of ATFa abolished E1a binding, while either mutation alone failed to impair these interactions.

Transcriptional activation by the adenovirus larger E1a product is mediated by members of the cellular transcription factor ATF family which can directly associate with E1a

1993 ◽  
Vol 13 (1) ◽  
pp. 561-570
Author(s):  
B Chatton ◽  
J L Bocco ◽  
M Gaire ◽  
C Hauss ◽  
B Reimund ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Metal Binding ◽  
Cdna Clones ◽  
Adenovirus E1a ◽  
Cellular Transcription Factor ◽  
Binding Domains ◽  
Mrna Gene ◽  
Conserved Region ◽  
Cellular Transcription

We recently isolated three cDNA clones encoding closely related proteins (ATFa1, ATFa2, and ATFa3) that belong to the activating transcription factor-cyclic AMP-responsive element family of cellular transcription factors. Using cotransfection experiments, we showed that these proteins mediate the transcriptional activation induced by the adenovirus E1a 13S mRNA gene product and that the zinc-binding domains present in both E1a conserved region 3 and the most N-terminal portion of the ATFa proteins play crucial roles in this activity. Reciprocal coimmunoprecipitation experiments demonstrated direct interactions between these proteins. Neither the conserved region 3 domain of E1a nor the N-terminal metal-binding element of ATFa is essential for these interactions. The simultaneous alteration of both the N-terminal and the C-terminal domains of ATFa abolished E1a binding, while either mutation alone failed to impair these interactions.

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.

Dimeric transcription factor families: it takes two to tango but who decides on partners and the venue?

1992 ◽  
Vol 103 (1) ◽  
pp. 9-14 ◽  
Author(s):  
K.A. Lee
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Binding ◽  
Experimental Evidence ◽  
Cdna Cloning ◽  
Transcriptional Activation ◽  
Effector Functions ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Dna Elements

Dimeric transcription factors that bind to DNA are often grouped into families on the basis of dimerization and DNA-binding specificities. cDNA cloning studies have established that members of the same family have structurally related dimerisation and DNA-binding domains but diverge in other regions that are important for transcriptional activation. These features lead to the straightforward suggestion that although all members of a family bind to similar DNA elements, individual members exhibit distinct transcriptional effector functions. This simple view is now supported by experimental evidence from those systems that have proved amenable to study. There are however some largely unaddressed questions that concern the mechanisms that allow family members to go about their business without interference from their highly related siblings. Here I will discuss some insights from studies of the bZIP class of transcription factors.

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.

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