The goals of this research program are to (a) isolate and characterize the genes encoding the major murine cAMP-dependent protein kinase (cAMPdPK) catalytic and regulatory subunits, (b) identify genes that may code for related or variant forms of these proteins and (c) examine the expression and regulation of these various genes during cell growth, differentiation and transformation. With respect to the latter goal we wish to (1) quantitate the transcription of cAMPdPK genes during differentiation in neuroblastoma cells and in 3T3-L1 adipocytes, (2) examine the transcriptional control of types I and II regulatory subunits in NIH/3T3 cells following transformation with either viral or cellular oncongenes, (3) compare these results to normal fluctuations in the expression of protein kinase genes during the cell cycle and (4) analyze the transcription of both regulatory and catalytic genes in S49 (kin) and other mutant cells. Our strategy, for obtaining mouse genes is to first isolate the appropriate cDNA clones from bovine tissues and then to use those sequences to identify corresponding mouse clones by direct cross-hybridization. This approach will be advantageous because of the availability of purified bovine cAMPdPK subunits, polyclonal and monoclonal antibodies directed against these subunits, and complete amino acid sequence data on the major bovine regulatory and catalytic proteins. Because of the high degree of cross-species conservation of cAMPdPK subunits we expect this approach to be successful. Consistent with this expectation, we have recently isolated a cDNA clone for the bovine RI subunit and demonstrated that it hybridizes to a unique sequence in both bovine and murine DNA under high stringency. We anticipate that these studies will lead to a further understanding of the role of cAMPdPK genes in the regulation of cell growth and differentiation in both normal and transformed cells.
