A novel Chlamydomonas reinhardtii gene potentially encoding a proline-, glycine- and tyrosine-rich protein (PGYRP)

Isolation and characterization of both the cDNA and the gene coding for a novel Chlamydomonas reinhardtii protein are here reported. Some peculiar features reported for Chlamydomonas species are recognizable in this mRNA, whose expression resulted to be heat-sensitive. The corresponding nuclear gene exhibits nine introns, all interrupting the coding region and is preceded by a proximal promoter region showing a putative TATA box and a number of sequences fitting heat shock-responsive elements. The deduced protein comprises 169 amino acids and has been called proline-, glycine-, and tyrosine-rich protein (PGYRP), due to the high content of these residues (about 30, 20, and 15%, respectively). The N-terminal region is proline-rich and contains several tandemly repeated hexapeptides sharing the consensus P[Q/P][P/A]GYP, the C-terminal region is rich in glycine, histidine, and lysine, therefore extremely basic; both these domains could be able to interact with other proteins. PGYRP may play a role as adaptor, involved in one or several cellular functions.