THE A-ALPHA MATING-TYPE TRANSCRIPTS OF SCHIZOPHYLLUM-COMMUNE

A alpha 1, A alpha 3, and A alpha 4 ds- and ss-DNA probes from the polymorphic An mating-type locus of Schizophyllum commune were used to probe Northern blots of poly(A(+)) RNA extracted from strains of various An mating types. The purpose of these experiments was to identify, map, and characterize the transcripts produced from the regions of the A alpha locus. The transcripts unique to An mating type map colinear with the open reading frames identified from DNA sequence and are encoded within the fragments which activate the A developmental pathway in transformation. These data confirm the existence and structure of the previously hypothesized Y and Z A alpha mating-type genes. Transcripts from the Y and Z genes are present in vegetative cells of homokaryons and dikaryons and in cells of the fruiting bodies. The presence of the transcripts throughout the life cycle is consistent with the model of Y and Z proteins as ''master switches'' of A-regulated development. (C) 1995 Academic Press, Inc.