The adenovirus E1A protein targets the SAGA but not the ADA transcriptional regulatory complex through multiple independent domains.
Expression of the adenovirus E1A protein in the simple eukaryote Saccharomyces cerevisiae inhibits growth. We tested four regions of E1A that alter growth and transcription in mammalian cells for their effects in yeast when expressed as fusions to the Gal4p DNA binding domain. Expression of the N-terminal/conserved region (CR) 1 or CR3, but not of the CR2 or the C-terminal portion of E1A, inhibited yeast growth. Growth inhibition was relieved by deletion of the genes encoding the yGcn5p, Ngg1p, or Spt7p components of the SAGA transcriptional regulatory complex, but not the Ahc1p component of the related ADA complex, indicating that the N-terminal/CR1 and CR3 regions of E1A target the SAGA complex independently. Expression of the pCAF acetyltransferase, a mammalian homologue of yGcn5p, also suppressed growth inhibition by either portion of E1A. Furthermore, the N-terminal 29 residues and the CR3 portion of E1A interacted independently with yGcn5p and pCAF in vitro. Thus, two separate regions of E1A target the yGcn5p component of the SAGA transcriptional activation complex. A subregion of the N-terminal/CR1 fragment spanning residues 30-69 within CR1 also inhibited yeast growth in a SAGA-dependent fashion. However, this region did not interact with yGcn5p or pCAF, suggesting that it makes a third contact with another SAGA component. Our results provide a new model system to elucidate mechanisms by which E1A and the SAGA complex regulate transcription and growth.
Shuen
Michael
M
Department of Microbiology and Immunology, London Regional Cancer Centre, The University of Western Ontario, 709 Commissioners Road E., London, Ontario N6A 4L6, Canada.
Avvakumov
Nikita
N
Walfish
Paul G
PG
Brandl
Chris J
CJ
Mymryk
Joe S
JS
D000123:Acetyltransferases / Q000037:antagonists & inhibitors / Q000502:physiology*; D048868:Adaptor Proteins, Signal Transducing; D017500:Adenovirus E1A Proteins / Q000737:chemistry / Q000502:physiology*; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000502:physiology*; D051548:Histone Acetyltransferases; D009097:Multienzyme Complexes / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000254:growth & development*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D015534:Trans-Activators / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*
C090575:ADA2 protein, S cerevisiae; D048868:Adaptor Proteins, Signal Transducing; D017500:Adenovirus E1A Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C106162:HFI1 protein, S cerevisiae; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; D011494:Protein Kinases