C. elegans unc-105 mutations affect muscle and are suppressed by other mutations that affect muscle
Park, E.C.; Horvitz, H.R.
Genetics 113(4): 853-867
1986
ISSN/ISBN: 0016-6731 PMID: 3744029 Document Number: 270605
Certain mutations in the unc-105 II gene of Caenorhabditis elegans have dominant effects on morphology and behaviour; animals become small, severely hypercontracted and paralyzed. These unc-105 mutants revert both spontaneously and with mutagens at high frequencies to a wild type phenotype. Most of the reversion events were intragenic, apparently because the null (loss-of-function) phenotype unc-105 is wild type. One revertant defined an extragenic suppressor locus, sup-20X. Such suppressor alleles of sup-20 are rare, and the apparent null phenotype of sup-20 was embryonic lethality. By constructing animals genetically mosaic for sup-20, it was shown that the primary effect of sup-20 is in muscle cells. Other mutations causing muscle defects, in unc-54 and unc-22, suppressed the hypercontracted phenotype of unc-105. The ease of identifying non-hyperconcentrated revertants of unc-105 mutants suggests a genetic selection scheme for the isolation of new mutants defective in muscle functioning.