Ae. Rougvie et V. Ambros, THE HETEROCHRONIC GENE LIN-29 ENCODES A ZINC-FINGER PROTEIN THAT CONTROLS A TERMINAL DIFFERENTIATION EVENT IN CAENORHABDITIS-ELEGANS, Development, 121(8), 1995, pp. 2491-2500
A hierarchy of heterochronic genes, lin-4, lin-14, lin-28 and lin-29,
temporally restricts terminal differentiation of Caenorhabitis elegans
hypodermal seam cells to the final molt. This terminal differentiatio
n event involves cell cycle exit, cell fusion and the differential reg
ulation of genes expressed in the larval versus adult hypodermis, lin-
29 is the most downstream gene in the developmental timing pathway and
thus it is the most direct known regulator of these diverse processes
, We show that lin-29 encodes a protein with five zinc fingers of the
(Cys)(2)-(HiS)(2) class and thus likely controls these processes by re
gulating transcription in a stage-specific manner, Consistent with thi
s role, a lin-29 fusion protein binds in vitro to the 5' regulatory se
quences necessary in vivo for expression of col-19, a collagen gene ex
pressed in the adult hypodermis. lin-29 mRNA is detected in the first
larval stage and increases in abundance through subsequent larval stag
es until the final molt, w hen lin-29 activity is required for termina
l differentiation.