Molecular cloning of the muscle gene unc-22 in Caenorhabditis elegans by Tc1 transposon tagging.

The previously described mutator system of Caenorhabditis elegans var. Bergerac has as one of its targets unc-22, a previously uncloned gene on chromosome IV important in assembly and function of the body wall musculature. By assuming that the mutator activity involved transposition of the repetitive element Tc1 into the unc-22 gene we have succeeded both in cloning the unc-22 gene and in demonstrating that Tc1 transposition is the principal basis of the mutator activity in the Bergerac strain. Although germ-line excision of Tc1 is sensitive to genetic background, somatic excision appears to be less so, suggesting that Tc1 movement is controlled differently in germ-line and somatic tissue. The availability of a transposon-based mutator system should aid in the cloning of additional genes in C. elegans, and the particular properties of this Tc1 system may provide information about the control of transposable element activity more generally.