A Cuticle Collagen Encoded by the lon-3 Gene May Be a Target of TGF-β Signaling in Determining Caenorhabditis elegans Body Shape

摘要

The signaling pathway initiated by the TGF-β family member DBL-1 in Caenorhabditis elegans controls body shape in a dose-dependent manner. Loss-of-function ( lf ) mutations in the dbl-1 gene cause a short, small body (Sma phenotype), whereas overexpression of dbl-1 causes a long body (Lon phenotype). To understand the cellular mechanisms underlying these phenotypes, we have isolated suppressors of the Sma phenotype resulting from a dbl-1(lf) mutation. Two of these suppressors are mutations in the lon-3 gene, of which four additional alleles are known. We show that lon-3 encodes a collagen that is a component of the C. elegans cuticle. Genetic and reporter-gene expression analyses suggest that lon-3 is involved in determination of body shape and is post-transcriptionally regulated by the dbl-1 pathway. These results support the possibility that TGF-β signaling controls C. elegans body shape by regulating cuticle composition.