title: Cyclic AMP signaling is required for function of the N-terminal and CR1 domains of adenovirus E1A in Saccharomyces cerevisiae.
abstract: We have constructed yeast vectors in which derivatives of the adenovirus E1A gene are expressed from the GAL1 promoter. Cells expressing E1A289 grow poorly and accumulate cells with a 1C DNA content. Using a series of E1A deletion mutants, we have identified three regions within the E1A protein that are necessary for the G1 growth phenotype; each deletion partially relieves the growth defect. These deletions span residues 4-25, 38-60 and 140-186, which fall within the N-terminal, CR1 and CR3 domains of E1A respectively. Expression of the first 82 residues of E1A, spanning just the N-terminal and CR1 domains, strongly inhibits yeast cell growth in G1 showing that these domains can function independently of other domains of E1A. Using this strong growth inhibition, we isolated a yeast mutant in the net1 gene that conferred resistance to the expression of E1A1-82. The mutant was insensitive to expression of both E1A1-82 and full length E1A, but remained sensitive to the toxicity caused by over-expression of a Gal4p-VP16 fusion. Finally, we found that the function of E1A in yeast depends on the cyclic AMP signaling pathway, providing a striking parallel with the action of E1A at the c-fos promoter in mammalian cells. These results suggest that a genetic analysis of the yeast model system will provide relevant new insights into mechanisms of gene regulation by E1A proteins.
mesh_terms: D017502:Adenovirus E2 Proteins / Q000737:chemistry / Q000502:physiology*; D000262:Adenylyl Cyclases / Q000378:metabolism; D001483:Base Sequence; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D000242:Cyclic AMP / Q000502:physiology*; D017931:DNA Primers / Q000737:chemistry; D005656:Fungal Proteins / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000502:physiology*; D017384:Sequence Deletion; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D020666:ras-GRF1
chemical_list: D017502:Adenovirus E2 Proteins; D018797:Cell Cycle Proteins; D017931:DNA Primers; D005656:Fungal Proteins; D020666:ras-GRF1; D000242:Cyclic AMP; D010749:Phosphoprotein Phosphatases; D000262:Adenylyl Cyclases