Identification of a second CtBP binding site in adenovirus type 5 E1A conserved region 3.
C-terminal binding protein (CtBP) binds to adenovirus early region 1A (AdE1A) through a highly conserved PXDLS motif close to the C terminus. We now have demonstrated that CtBP1 also interacts directly with the transcriptional activation domain (conserved region 3 [CR3]) of adenovirus type 5 E1A (Ad5E1A) and requires the integrity of the entire CR3 region for optimal binding. The interaction appears to be at least partially mediated through a sequence ((161)RRNTGDP(167)) very similar to a recently characterized novel CtBP binding motif in ZNF217 as well as other regions of CR3. Using reporter assays, we further demonstrated that CtBP1 represses Ad5E1A CR3-dependent transcriptional activation. Ad5E1A also appears to be recruited to the E-cadherin promoter through its interaction with CtBP. Significantly, Ad5E1A, CtBP1, and ZNF217 form a stable complex which requires CR3 and the PLDLS motif. It has been shown that Ad513SE1A, containing the CR3 region, is able to overcome the transcriptional repressor activity of a ZNF217 polypeptide fragment in a GAL4 reporter assay through recruitment of CtBP1. These results suggest a hitherto-unsuspected complexity in the association of Ad5E1A with CtBP, with the interaction resulting in transcriptional activation by recruitment of CR3-bound factors to CtBP1-containing complexes.
Cancer Research UK, Institute of Cancer Studies, University of Birmingham, Birmingham, United Kingdom.
Rachel K
RK
Bruton
Peter
P
Pelka
Katie L
KL
Mapp
Gregory J
GJ
Fonseca
Joseph
J
Torchia
Andrew S
AS
Turnell
Joe S
JS
Mymryk
Roger J A
RJ
Grand
D017500:Adenovirus E1A Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001665:Binding Sites; D018288:Carcinoma, Small Cell / Q000378:metabolism; D045744:Cell Line, Tumor; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D017930:Genes, Reporter; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D045325:HCT116 Cells; D019073:HT29 Cells; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000032:analysis; D008175:Lung Neoplasms / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D012516:Osteosarcoma / Q000378:metabolism; D010957:Plasmids; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
D017500:Adenovirus E1A Proteins; D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein; D008156:Luciferases; D005982:Glutathione Transferase