Genomic organization, expression, and analysis of the troponin C gene pat-10 of Caenorhabditis elegans

We have cloned and characterized the troponin C gene, pat-10 of the nematod e Caenorhabditis elegans. At the amino acid level nematode troponin C is mo st similar to troponin C of Drosophila (45% identity) and cardiac troponin C of vertebrates. Expression studies demonstrate that this troponin is expr essed in body wall muscle throughout the life of the animal. Later, vulval muscles and anal muscles also express this troponin C isoform. The structur al gene for this troponin is pat-10 and mutations in this gene lead to anim als that arrest as twofold paralyzed embryos late in development. We have s equenced two of the mutations in pat-10 and both had identical two mutation s in the gene; one changes D64 to N and the other changes W153 to a termina tion site. The missense alteration affects a calcium-binding site and elimi nates calcium binding, whereas the second mutation eliminates binding to tr oponin I. These combined biochemical and in vivo studies of mutant animals demonstrate that this troponin is essential for proper muscle function duri ng development.