Ultrastructural immuno-localization of CUT-1 and CUT-2 antigenic sites in the cuticles of the nematode Caenorhabditis elegans.

CUT-1 and CUT-2 are two distinct proteins found in cuticlin, the insoluble residue of the cuticles of the nematode Caenorhabditis elegans. They are the products of genes which have been previously characterized molecularly. These proteins have been expressed as recombinant in Escherichia coli and specific antisera have been raised against them. The experiments reported here regard their ultrastructural immuno-gold localization either on purified cuticles or on whole worms of various stages of development of Caenorhabditis elegans. A location in the cortical layer of the isolated cuticles is common to all stages, whereas there is a dauer specific location in the fibrous ribbon underneath the alae. These localizations are compared with immuno-labelling obtained using a serum raised against the whole cuticlin residue. CUT-1 and CUT-2 epitopes are easily and specifically lost during conventional chemical fixation.