Alternative splicing of L7/pep2 gene results in truncated protein
The L7/pcp2 have been described for the fi rst time in 1988 by two independent groups. Transcripted RNA is source of 99-aminoacid peptide of 16kD with some homology to NH2-terminal part of PDGF. pcp2 protein is known for its very specifi c expression in cerebellar Purkinje cells and bipolar retinal neurons. Initial experiments showed, that isolated Purkinje cell specifi c mRNA did not hybridize to cerebellar mRNA from mice with Purkinje cell degeneration mutation. It was a strong indication, that pcp2 protein could play an important role in Purkinje cell physiology and development. Mice null mutant for that gene however, do not display any morphological or physiological abnormalities. Up to now there are only few experimental data suggesting the function of pcp2 protein. Experiments on G protein interactions revealed pcp2 as possible GDP exchange factor for Go subunit. This function of pcp2 depends on the presence of G-protein regulatory motifs (GPR) known also as GoLoco motifs. Our experiments regarding expression pattern of pcp2, revealed a new splice variant of its mRNA – pcp2B. Additional ~350bp long band was always prominent in PCR products amplifi ed on cDNA from mouse eye preparations. Incorporation of the new exon 3B results in truncated protein, because of STOP codon present in its structure. Missing region consists of some putative phosphorylation sites with possible biological function important the L7/pcp2 protein.