Cuticlin is the insoluble residue of the nematode cuticle which remains after treatment of the cuticle with SDS and 2-ME. The cloning and characterization of two cuticlin genes,
cut-1 and
cut-2, from C. elegans has led to the search for homologs in parasitic worms of medical importance. Using a
cut-1 probe has revealed the presence of homologs in a variety of parasitic nematodes. Two Ascaris
cut-1 homologs were identified by screening an adult genomic library with a
cut-1 fragment corresponding to a domain which is largely conserved in a
cut-1 homolog of the plant parasitic nematode Meloidogyne artiella. Both genes show strong homology to specific stretches of C. elegans
cut-1. Ascaris
cut-1 primers are now being used in RT-PCR reactions on first-strand cDNA from different life-cycle stages of the parasite, in order to establish a transcription pattern for the gene. In order to directly identify the full-length cDNA of the Brugia
cut-1 homolog,
cut-1 specific primers were used in RT-PCR reactions using first-strand cDNA from various Brugia life-cycle stages as the template. PCR products were cloned and are in the process of being sequenced to establish homology with the C. elegans and Ascaris
cut-1 genes. Preliminary RT-PCR implies that the
cut-1 homolog in Brugia is transcribed at specific points in the life-cycle associated with maximal growth, presumably preceding a moult, and is not transcribed in the adult worm.