CGC Bibliography Paper 3119

Identification of heterochronic mutants in Caenorhabditis elegans: Temporal misexpression of a collagen::Green Fluorescent Protein fusion gene.

Abrahante JE, Miller EA, Rougvie AE

Medline:

98315098

Citation:

Genetics 149: 1335-1351 1998

Type:

ARTICLE

Genes:

col-19 lin-4 lin-14 lin-28 lin-29 lin-42 lin-58 ccDf11 yDf4 yDf8

Abstract:

The heterochronic genes lin-4, lin-14, lin-28, and lin-29 specify the timing of lateral hypodermal seam cell terminal differentiation in Caenorhabditis elegans. We devised a screen to identify additional genes involved in this developmental timing mechanism based on identification of mutants that exhibit temporal misexpression from the col-19 promoter, a downstream target of the heterochronic gene pathway. We fused the col-19 promoter to the green fluorescent protein gene (gfp) and demonstrated that hypodermal expression of the fusion gene is adult-specific in wild-type animals and temporally regulated by the heterochronic gene pathway. We generated a transgenic strain in which the col-19::gfp fusion construct is not expressed because of mutation of lin-4 which prevents seam cell terminal differentiation. We have identified and characterized 26 mutations that restore col-19::gfp expression in the lin 4 mutant background. Most of the mutations also restore other aspects of the seam cell terminal differentiation program that are defective in lin-4 mutant animals. Twelve mutations are alleles of three previously identified genes known to be required for proper timing of hypodermal terminal differentiation. Among these are four new alleles of lin-42, a heterochronic gene for which a single allele had been described previously. Two mutations define a new gene, lin-58. When separated from lin-4, the lin-58 mutations cause precocious seam cell terminal differentiation and thus define a new member of the heterochronic gene pathway.