CAENORHABDITIS-ELEGANS SQT-3 MUTANTS HAVE MUTATIONS IN THE COL-1 COLLAGEN GENE

sqt-3 mutants of Caenorhabditis elegans form dumpy larvae and adults a nd display allele-specific defects in locomotion, fertility, and viabi lity. We have determined that the sqt-3 locus encodes COL-1 collagen. We physically mapped the col-1 gene to a cosmid on chromosome V whose position is consistent with the location of the sqt-3 gene. We also ob served morphological defects in sqt-3 mutants at stages that correlate with the mRNA expression patterns of col-1. Sequence analysis of the col-1 gene in the three temperature-sensitive mutants revealed that ea ch allele of sqt-3 has a unique missense mutation causing arginine or glutamic acid to replace glycine in a Gly-X-Y triple helical domain. T hese glycine substitutions may result in longer non-collagenous domain s, which may decrease the thermal stability or impart additional flexi bility to mutant trimmers. In addition, we describe four corrections t o the published sequence of col-1, including one fifteen nucleotide ad dition that completes a conserved domain in the amino terminal coding region. (C) 1994 Wiley-Liss, Inc.