THE HSP70 GENE FAMILY OF NEUROSPORA-CRASSA - CLONING, SEQUENCE-ANALYSIS, EXPRESSION, AND GENETIC-MAPPING OF THE MAJOR STRESS-INDUCIBLE MEMBER

The gene encoding the major heat shock-inducible member of the HSP70 f amily of Neurospora crassa was cloned and characterized. The 5' nontra nscribed region shows the presence of consensus sequence motifs resemb ling the classical heat shock elements found in many heat shock-respon sive eukaryotic promoters, as well as metal-responsive-element sequenc es. The coding region of the gene contains four introns with boundarie s and internal consensus motifs typical of genes of filamentous fungi. None of the other stress-inducible hsp70 genes of fungal origin have, so far, been reported to contain introns, The sequence adjoining the transcriptional initiation zone shows the presence of prominent CT-ric h stretches, characteristic of highly expressed fungal genes, The dedu ced amino acid sequence corresponds to a 646-residue polypeptide, with a calculated molecular mass of 70,561 Da and an average pi of 6.01, e xhibiting strong sequence homology with many other eukaryotic HSP70s, with typical HSP70 family signatures 1 and 2 and a bipartite nuclear t argeting sequence, Experiments with primer extension revealed the pres ence of one minor and two major transcriptional start sites, This gene , designated hsps-1, was mapped to a locus on the left arm of linkage group II, in close proximity to the AR-30 translocation breakpoint.