glp-1 can substitute for lin-12 in specifying cell fate decisions in Caenorhabditis elegans.
Members of the lin-12/Notch gene family encode receptors for intercellular signals and are found throughout the animal kingdom. In many animals, the presence of at least two lin-12/Notch genes raises the issue of the significance of this duplication and divergence. In Caenorhabditis elegans, two lin-12/Notch genes, lin-12 and glp-1, encode proteins that are 50% identical, with different numbers of epidermal growth factor-like motifs in their extracellular domains. Many of the cell fate decisions mediated by lin-12 and glp-1 are distinct. Here, we express glp-1 protein under the control of lin-12 regulatory sequences in animals lacking endogenous lin-12 activity and find that glp-1 can substitute for lin-12 in mediating cell fate decisions. These results imply that the lin-12 and glp-1 proteins are biochemically interchangeable, sharing common ligand and effector proteins, and that the discrete lin-12 and glp-1 mutant phenotypes result from differential gene expression. In addition, these results suggest that the duplicate lin-12/Notch genes found in vertebrates may also be biochemically interchangeable.
Fitzgerald
K
K
Department of Molecular Biology, Princeton University, NJ 08544.
Wilkinson
H A
HA
Greenwald
I
I
D000818:Animals; D017173:Caenorhabditis elegans / Q000033:anatomy & histology / Q000196:embryology* / Q000235:genetics; D004627:Embryonic Induction / Q000235:genetics*; D017238:Genes, Helminth / Q000502:physiology*; D009024:Morphogenesis / Q000235:genetics