Worm Breeder's Gazette 13(2): 57 (February 1, 1994)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

The Troponin C Gene, tnc-1, of Caenorhabditis elegans: Genome Structure and Mutation Sites of pat-10

S. Kitamura, B. Williams, Y. Sakube, S. Matsumoto and H. Kagawa

What the problem of muscle studies are how many components are concerned
and are functioned. Genetic approach is much easier to isolate a functional molecule
without knowing its character. There are some uncoordinated( unc ) mutants which
cause muscle gene defects in Caenorhabditis elegans. The animal has mainly two
muscles; pharyngeal and body wall muscles. To understand muscle structure and
function it is useful to clone all genes for the muscle components and to determine the
mutation site of the gene. Even though total genome projects are going well and so
many mutants are isolated, there are still missing the knowledge about main
components of muscle.
  We have isolated muscle protein genes of Caenorhabditis elegans that are
especially concerning calcium signaling. There were ryanodine receptor,
Tropomyosin(Tm), Troponin(Tn)C, and Tnl genes which were cloned by screening a
cDNA expression library with a probe of a vertebrate homologue or antiserum of each
protein. All of those sequences of muscle proteins had high homology to those of
vertebrate cardiac proteins. Comparison of genomic and cDNA structures confirmed
the number and the pattern of isoforms. Only one isoform was found in each of Tnl
and TnC genes. Interestingly the intron/exon arrangement of the TnC gene was most
similar to that of the gene coding for TnC isoform of human fast skeletal muscle.
Location on cosmid clone and map position of the tnc-1 gene was presented at the left
central of LG l. pat-10 mutant was mapped on the same place and was rescued with
YAC Y55F5 but was hardly rescued with pTNC1 which contained 3.47kb of tnc-1 gene
with 1.3 kb 5'-UTR. We hope pTNC2 having 7.7kb fragment at the 5' end can rescue
pat phenotype. The troponin C molecule of pat-10 mutant missed nine amino acids of
C-terminus by changing W to termination. We are confirming whether there was a
different mutation site in the molecule or in the other allele. We are also doing
microinjection experiment to know the stage and space of the gene expression.