Four Drosophila heat shock genes at 67B: characterization of recombinant plasmids.

A 33 kilobase region of the 67B locus of Drosophila melanogaster genome has been isolated. The genes for the 27K, 26K, 23K and 22K heat shock induced proteins are contained within an 11 kb segment. the 27K gene, approximately 1.4 kb in length, and the 23K gene, approximately 1.0 kb in length, are separated by about 1.5 kb of spacer DNA; a third block of transcription, which encodes the 26K gene, is approximately 1.1 kb in length, and is separated from the gene for the 23K protein by 4.5 kb of spacer DNA. The 22K gene is located approximately 1.2 kb from the 26K gene. The RNAs encoding the 27K, 23K and 22K genes are transcribed from the same DNA strand. With the assignment of the four small heat shock induced proteins to 67B, genes for all seven major heat shock induced proteins have no been mapped cytologically.