1. The heat shock response of the nematode Caenorhabditis elegans has been characterized. 2. There are at least nine genes in the
hsp70 multigene family of C. elegans. 3. Five of the
hsp70 genes have been characterized and assigned to one of at least three
hsp70 gene subfamilies. One of the subfamilies consists of an
hsp70 protein that has the potential to be translocated into the endoplasmic reticulum and another subfamily consists of a protein that has the potential to be translocated into the mitochondria. 4. The C. elegans
hsp70 multigene family has several unique characteristics including introns in the heat inducible
hsp70 genes, at least one trans-spliced
hsp70 mRNA and two
grp78 related genes, one of which is highly heat inducible. 5. The identification and characterization of C. elegans
hsp70 multigene family is the basis for a genetic characterization of the regulation and function of a gene family during the development of a multicellular eukaryote.