Isolation and sequence of a developmentally regulated putative novel gene, priA, from the basidiomycete Lentinus edodes

Screening for gene(s) homologous to v-Ha- ras (Harvey rat sarcoma viral ras gene) in the basidiomycete, Lentinus edodes, resulted in the isolation of a novel gene (designated priA), in addition to a ras gene homologue [Hori et al., Gene 105 (1991) 91–96]. The priA gene has a coding capacity of 258 amino acids (aa) interrupted by two short putative introns. The 5′-upstream region of priA contains GGGCGG box, CCAAT box, TATAAA box and CT sequecce elements in 5′→3′ order. One transcription start point ( tsp) was located 10 nucleotides upstream from a TATAAA box and another tsp just in a CT sequence. The deduced PRIA protein (26.7 kDa), rich in Ser (42 residues), Pro (29 residues) and Thr (27 residues), contained different types of putative zinc-binding motifs. It initiated with a hydrophobic as sequence and terminated with the unique sequence, Cys-Aaa-Aaa-Xaa (where Aaa is aliphatic aa and Xaa is any aa), implying an association with the inner membrane surface via acylation of the Cys residue. The priA gene expression was found to be developmentally regulated with primordia/immature fruiting bodies having much higher levels of priA transcript. Preprimordial mycelia and mature fruiting bodies, however, contain very low levels of priA transcript. The priA gene may play a role during the beginning of fruiting.