We have continued our analysis of a novel protein kinase gene (termed c- NO) encoding a protein with extensive homology to the raf oncogene. Antibodies have been generated to kinase peptides and recombinant protein fragments and have been used to identify the kinase protein by immunoprecipitation and western blotting. Preliminary experiments have identified a protein of 70-80 Kd in the nucleus of a variety of cell types. In vitro mRNA transcription and translation are being used to make kinase protein for functional assays and to identify cellular protein substrates. Because of its unusual basic amino acid repeats in the regulatory domain, this kinase appears to be related to other nucleolar RNA binding proteins especially the HIV REV and TAT regulatory proteins. Current experiments are directed at defining the physiological catalytic function of the kinase protein and at determining its nucleic acid binding potential.
