The Caenorhabditis elegans hsp70 gene family: a molecular genetic characterization

We have isolated genomic clones representing six distinct members of the Caenorhabditis elegans 70-kDa heat-shock protein gene ( hsp70) family. Each member exists as a single copy element in the C. elegans genome. Transcripts of four of the hsp70 genes have been detected by Northern-blot analysis. One member, hsp70C, appears to be a heat-shock-cognate hsp70 gene ( hsc70) since its transcription is developmentally regulated and is not increased in response to heat shock. Transcripts of another gene, hsp70A, are abundant in control worms and are also increased (two- to six-fold) upon heat shock. Nucleotide sequencing of genomic and cDNA clones of hsp70A reveals that it is highly homologous to Drosophila and yeast heat-shock-inducible and heat-shock-cognate hsp70 genes. Three DNA elements homologous to the heat-shock promoter, 5'-C- -GAA- -TTC--G-3' are located upstream from the Hsp70A-coding region. We find that hsp70A contains three introns, one of which is in a similar position with an intron in the Drosophila hsc1 and hsc2 genes. Finally, utilizing strain-specific restriction fragment length differences, we have mapped the chromosomal position of hsp70A to the far right of chromosome IV.