The goal of this proposal is to finish cloning and partially characterize the gene encoding the novel tyrosine phosphoprotein, Sob1. Sob1 is important in regulating expression of the proto- oncogene c-fos. As such, Sob1 is likely to play a role in oncogenesis. In addition, the original studies of Sob1 were in T cells, where Sob1 was important in regulating very early stages of T cell activation, and therefore in regulating immune system function. A method has been developed for purification of Sob1 and by the time the fellowship would start, amino acid sequencing will have been done on part of Sob1. A library will be screened using probes developed from the AA sequence. A full-length clone will be created by RACE, and the nucleotide sequence obtained. This sequence will be studied for functional motifs and to identify the relevant tyrosine residue that is phosphorylated. Tissue specific expression will be evaluated using commercially available blots and rudimentary mutations will be created by truncation or site-directed mutagenesis.
