Drosophila gene related to the major heat shock-induced gene is transcribed at normal temperatures and not induced by heat shock.

Abstract

A gene related to the major heat shock-induced (hsp70) gene of Drosophila was isolated from the sibling species D. melanogaster and D. simulans. This heat shock-cognate (hsc70) gene is present at cytological locus 70C. The primary sequence of .apprx. 1/3 of the protein-coding region was compared with that of the hsp70 gene; 72% homology of the base sequence and 74% homology of the deduced amino acid sequence was found. In the codon specifying amino acid 66, the hsc70 gene contains an insertion of 1.7 kilobases; the hsp70 genes contain no intervening sequences. The sequence at the 5'' and 3'' junctions of the insertion is similar to that found in many intervening sequences. c[complementary]DNA extension experiments indicate the hsc70 gene is transcribed at normal temperatures in adult flies and that transcription is not enhanced by heat treatment.