The heterochronic genes lin-4, lin-14, lin-28, and lin-29 control the timing of specific postembryonic developmental events in C. elegans. The experiments described here examine how these four genes interact to control a particular stage-specific event of the lateral hypodermal cell lineages. This event, termed the "larva-to-adult switch" (L/A switch), involves several coordinate changes in the...

In the two nematode species Caenorhabditis elegans and Pristionchus pacificus the vulva equivalence group in the central body region is specified by the Hox gene lin-39. C. elegans lin-39 mutants are vulvaless and the vulval precursor cells fuse with the surrounding hypodermis, whereas in P. pacificus lin-39 mutants the vulval precursor cells die by apoptosis. Mechanistically, LIN-39 might inhi...

In this issue of Cell, Inoue et al. (2004) reports that LIN-18, an atypical receptor tyrosine kinase related to mammalian Ryk and Drosophila Derailed, mediates Wnt signaling in parallel to LIN-17/Frizzled (Fz) during worm vulval development. LIN-18/Ryk and LIN-17/Fz appear to exhibit distinct Wnt specificity, and surprisingly, the LIN-18 intracellular domain may be dispensable.

LIN-1 is an ETS domain protein. A receptor tyrosine kinase/Ras/mitogen-activated protein kinase signaling pathway regulates LIN-1 in the P6.p cell to induce the primary vulval cell fate during Caenorhabditis elegans development. We identified 23 lin-1 loss-of-function mutations by conducting several genetic screens. We characterized the molecular lesions in these lin-1 alleles and in several pr...

The Caenorhabditis elegans synthetic multivulva (synMuv) genes act redundantly to antagonize the specification of vulval cell fates, which are promoted by an RTK/Ras pathway. At least 26 synMuv genes have been genetically identified, several of which encode proteins with homologs that act in chromatin remodeling or transcriptional repression. Here we report the molecular characterization of two...

lin-4 is essential for the normal temporal control of diverse postembryonic developmental events in C. elegans. lin-4 acts by negatively regulating the level of LIN-14 protein, creating a temporal decrease in LIN-14 protein starting in the first larval stage (L1). We have cloned the C. elegans lin-4 locus by chromosomal walking and transformation rescue. We used the C. elegans clone to isolate ...

Induction of vulval fates in the C. elegans hermaphrodite is mediated by a signal transduction pathway involving Ras and MAP kinase. Previous genetic analysis has suggested that two potential targets of this pathway in the vulva precursor cells are two novel proteins, LIN-25 and SUR-2. In this report, we describe further studies of lin-25. The results of a genetic mosaic analysis together with ...

1 1Institute of Earth Sciences, Academia Sinica, Nankang, Taipei, Taiwan, ROC 2Institute of Statistics, National Central University, Chungli, Taiwan, ROC 3Institute of Space Science, National Central University, Chungli, Taiwan, ROC 4Department of Geosciences, National Taiwan Normal University, Taipei, Taiwan, ROC *Corresponding author address: Prof. C. H. Lin, Institute of Earth Sciences, Acad...

Dr. Haifan Lin is professor of Cell Biology at Yale University, where he studies the mechanism of stem cell self-renewal in fruit flies, mice, and human cancer cells. Recently named director of the Yale Stem Cell Center, Dr. Lin has made seminal contributions to the stem cell field, most notably his demonstration of the stem cell niche theory using the fruit fly model, his discovery of the PIWI...

LIM homeobox family members regulate a variety of cell fate choices during animal development. In C. elegans, mutations in the LIM homeobox gene lin-11 have previously been shown to alter the cell division pattern of a subset of the 2 degrees lineage vulval cells. We demonstrate multiple functions of lin-11 during vulval development. We examined the fate of vulval cells in lin-11 mutant animals...