scholarly journals Adenovirus E1a prevents the retinoblastoma gene product from repressing the activity of a cellular transcription factor.

1992 ◽  
Vol 11 (7) ◽  
pp. 2603-2610 ◽  
Author(s):  
M. Zamanian ◽  
N.B. La Thangue
Keyword(s):  
Transcription Factor ◽  
Gene Product ◽  
Retinoblastoma Gene ◽  
Adenovirus E1a ◽  
Cellular Transcription Factor ◽  
Retinoblastoma Gene Product ◽  
Cellular Transcription

scholarly journals Protein domains governing interactions between E2F, the retinoblastoma gene product, and human papillomavirus type 16 E7 protein.

1993 ◽  
Vol 13 (2) ◽  
pp. 953-960 ◽  
Author(s):  
P S Huang ◽  
D R Patrick ◽  
G Edwards ◽  
P J Goodhart ◽  
H E Huber ◽  
...  
Keyword(s):  
Amino Acids ◽  
Complex Formation ◽  
Gene Product ◽  
Mammalian Cells ◽  
Protein Product ◽  
Human Papillomaviruses ◽  
Retinoblastoma Gene ◽  
Adenovirus E1a ◽  
Cellular Transcription Factor ◽  
Retinoblastoma Gene Product

Human papillomaviruses (HPVs) are the etiological agents for genital warts and contribute to the development of cervical cancer in humans. The HPV E7 gene product is expressed in these diseases, and the E7 genes from HPV types 16 and 18 contribute to transformation in mammalian cells. Mutation and deletion analysis of this gene suggests that the transforming activity of the protein product resides in the same domain as that which is directly involved in complex formation with the retinoblastoma gene product (pRB). This domain is one of two conserved regions (designated CRI and CRII) shared by E7 and other viral oncoproteins which bind pRB, including adenovirus E1A protein. Binding of HPV type 16 E7 protein to pRB has previously been shown to affect pRB's ability to bind DNA and to form complexes with other cellular proteins. In the current study, we map the functional interaction between E7 protein and pRB by monitoring the association between a 60-kDa version of the pRB, pRB60, and the cellular transcription factor E2F. We observe that CRII of E7 (amino acids 20 to 29), which completely blocks binding of full-length E7 protein, is necessary but not sufficient to inhibit E2F/pRB60 complex formation. While CRI of E1A (amino acids 37 to 55) appears to be sufficient to compete with E2F for binding to pRB60, the equivalent region of E7 is neither necessary nor sufficient. Only E7 fragments that contained both CRII and at least a portion of the zinc-binding domain (amino acids 60 to 98) inhibited E2F/pRB60 complex formation. These results suggest that pRB60 associates with E7 and E2F through overlapping but distinct domains.

Protein domains governing interactions between E2F, the retinoblastoma gene product, and human papillomavirus type 16 E7 protein

1993 ◽  
Vol 13 (2) ◽  
pp. 953-960
Author(s):  
P S Huang ◽  
D R Patrick ◽  
G Edwards ◽  
P J Goodhart ◽  
H E Huber ◽  
...  
Keyword(s):  
Amino Acids ◽  
Complex Formation ◽  
Gene Product ◽  
Mammalian Cells ◽  
Protein Product ◽  
Human Papillomaviruses ◽  
Retinoblastoma Gene ◽  
Adenovirus E1a ◽  
Cellular Transcription Factor ◽  
Retinoblastoma Gene Product

Human papillomaviruses (HPVs) are the etiological agents for genital warts and contribute to the development of cervical cancer in humans. The HPV E7 gene product is expressed in these diseases, and the E7 genes from HPV types 16 and 18 contribute to transformation in mammalian cells. Mutation and deletion analysis of this gene suggests that the transforming activity of the protein product resides in the same domain as that which is directly involved in complex formation with the retinoblastoma gene product (pRB). This domain is one of two conserved regions (designated CRI and CRII) shared by E7 and other viral oncoproteins which bind pRB, including adenovirus E1A protein. Binding of HPV type 16 E7 protein to pRB has previously been shown to affect pRB's ability to bind DNA and to form complexes with other cellular proteins. In the current study, we map the functional interaction between E7 protein and pRB by monitoring the association between a 60-kDa version of the pRB, pRB60, and the cellular transcription factor E2F. We observe that CRII of E7 (amino acids 20 to 29), which completely blocks binding of full-length E7 protein, is necessary but not sufficient to inhibit E2F/pRB60 complex formation. While CRI of E1A (amino acids 37 to 55) appears to be sufficient to compete with E2F for binding to pRB60, the equivalent region of E7 is neither necessary nor sufficient. Only E7 fragments that contained both CRII and at least a portion of the zinc-binding domain (amino acids 60 to 98) inhibited E2F/pRB60 complex formation. These results suggest that pRB60 associates with E7 and E2F through overlapping but distinct domains.

Retinoblastoma gene product activates expression of the human TGF-β2 gene through transcription factor ATF-2

Nature ◽  
1992 ◽  
Vol 358 (6384) ◽  
pp. 331-334 ◽  
Author(s):  
Seong-Jin Kim ◽  
Susanne Wagner ◽  
Fang Liu ◽  
Michael A. O'Reilly ◽  
Paul D. Robbins ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Gene Product ◽  
Retinoblastoma Gene ◽  
Retinoblastoma Gene Product

Identification of distinct roles for separate E1A domains in disruption of E2F complexes

1993 ◽  
Vol 13 (11) ◽  
pp. 7029-7035
Author(s):  
M A Ikeda ◽  
J R Nevins
Keyword(s):  
Transcription Factor ◽  
Gene Product ◽  
Protein Complexes ◽  
Cyclin A ◽  
Regulatory Proteins ◽  
Retinoblastoma Gene ◽  
Adenovirus E1a ◽  
E2f Transcription Factor ◽  
Cdk2 Complex ◽  
Equilibrium Dissociation

The adenovirus E1A protein can disrupt protein complexes containing the E2F transcription factor in association with cellular regulatory proteins such as the retinoblastoma gene product (Rb) and the Rb-related p107 protein. Previous experiments have shown that the CR1 and CR2 domains of E1A are required for this activity. We now demonstrate that the CR2 domain is essential for allowing E1A to interact with the E2F-Rb or the E2F-p107-cyclin A-cdk2 complex. Multimeric complexes containing E1A can be detected when the CR1 domain has been rendered inactive by mutation. In addition, the E1A CR1 domain, but not the CR2 domain, is sufficient to prevent the interaction of E2F with Rb or p107. On the basis of these results, we suggest a model whereby the CR2 domain brings E1A to the E2F complexes and then, upon a normal equilibrium dissociation of Rb or p107 from E2F, the E1A CR1 domain is able to block the site of interaction on Rb or p107, thereby preventing the re-formation of the complexes.

scholarly journals Identification of distinct roles for separate E1A domains in disruption of E2F complexes.

1993 ◽  
Vol 13 (11) ◽  
pp. 7029-7035 ◽  
Author(s):  
M A Ikeda ◽  
J R Nevins
Keyword(s):  
Transcription Factor ◽  
Gene Product ◽  
Protein Complexes ◽  
Cyclin A ◽  
Regulatory Proteins ◽  
Retinoblastoma Gene ◽  
Adenovirus E1a ◽  
E2f Transcription Factor ◽  
Cdk2 Complex ◽  
Equilibrium Dissociation

The adenovirus E1A protein can disrupt protein complexes containing the E2F transcription factor in association with cellular regulatory proteins such as the retinoblastoma gene product (Rb) and the Rb-related p107 protein. Previous experiments have shown that the CR1 and CR2 domains of E1A are required for this activity. We now demonstrate that the CR2 domain is essential for allowing E1A to interact with the E2F-Rb or the E2F-p107-cyclin A-cdk2 complex. Multimeric complexes containing E1A can be detected when the CR1 domain has been rendered inactive by mutation. In addition, the E1A CR1 domain, but not the CR2 domain, is sufficient to prevent the interaction of E2F with Rb or p107. On the basis of these results, we suggest a model whereby the CR2 domain brings E1A to the E2F complexes and then, upon a normal equilibrium dissociation of Rb or p107 from E2F, the E1A CR1 domain is able to block the site of interaction on Rb or p107, thereby preventing the re-formation of the complexes.

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 A bipartite nuclear localization signal in the retinoblastoma gene product and its importance for biological activity.

1993 ◽  
Vol 13 (8) ◽  
pp. 4588-4599 ◽  
Author(s):  
E Zacksenhaus ◽  
R Bremner ◽  
R A Phillips ◽  
B L Gallie
Keyword(s):  
Biological Activity ◽  
Transcription Factors ◽  
Gene Product ◽  
Nuclear Localization ◽  
Simian Virus 40 ◽  
T Antigen ◽  
Retinoblastoma Gene ◽  
C Terminus ◽  
Retinoblastoma Gene Product ◽  
Cellular Transcription

The retinoblastoma gene product, p110RB1, appears to regulate cell growth by modulating the activities of nuclear transcription factors. The elements that specify the transport of p110RB1 into the nucleus have not yet been explored. We now report the identification of a basic region, KRSAEGGNPPKPLKKLR, in the C terminus of p110RB1, which has sequence similarity to known bipartite nuclear localization signals (NLSs). A two-amino-acid mutation introduced into this putative NLS [to give mutant NLS(NQ)] or deletion of the entire NLS (delta NLS) abrogated exclusive nuclear localization, yielding proteins which were distributed either equally throughout the cell or predominantly in the cytoplasm. A mutant protein [NLS(NQ)/delta 22] containing both the mutated NLS and a deletion of exon 22, previously shown to disrupt the interaction of p110RB1 with several cellular transcription factors and oncoproteins, accumulated only in the cytoplasm. When fused to the C terminus of Escherichia coli beta-galactosidase, the RB1 NLS directed this protein to the nucleus, indicating that the motif is not only necessary but also sufficient for nuclear transport. Neither NLS(NQ) nor delta NLS was hyperphosphorylated in vivo, but both retained their abilities to interact, in vitro, with simian virus 40 large T antigen, adenovirus E1a, and the cellular transcription factor E2F. When transfected at multiple copy number, the NLS mutant alleles displayed reduced biological activity, measured by inhibition of growth of the osteogenic sarcoma cell line Saos-2, which has no wild-type RB1. Naturally occurring mutations and deletions in exon 25 of RB1 which disrupt the NLS may lead to partial or complete inactivation of p110RB1 and may be responsible for some retinoblastoma and other tumors.

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.

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