12399309

pubmed:Citation

22

Development of the vulva in C. elegans is mediated by the combinatorial action of several convergent regulatory inputs, three of which, the Ras, Wnt and Rb-related pathways, act by regulating expression of the lin-39 Hox gene. LIN-39 specifies cell fates and regulates cell fusion in the mid-body region, leading to formation of the vulva. In the lateral seam epidermis, differentiation and cell fusion have been shown to be regulated by two GATA-type transcription factors, ELT-5 and -6. We report that ELT-5 is encoded by the egl-18 gene, which was previously shown to promote formation of a functional vulva. Furthermore, we find that EGL-18 (ELT-5), and its paralogue ELT-6, are redundantly required to regulate cell fates and fusion in the vulval primordium and are essential to form a vulva. Elimination of egl-18 and elt-6 activity results in arrest by the first larval stage; however, in animals rescued for this larval lethality by expression of ELT-6 in non-vulval cells, the post-embryonic cells (P3.p-P8.p) that normally become vulval precursor cells often fuse with the surrounding epidermal syncytium or undergo fewer than normal cell divisions, reminiscent of lin-39 mutants. Moreover, egl-18/elt-6 reporter gene expression in the developing vulva is attenuated in lin-39(rf) mutants, and overexpression of egl-18 can partially rescue the vulval defects caused by reduced lin-39 activity. LIN-39/CEH-20 heterodimers bind two consensus HOX/PBC sites in a vulval enhancer region of egl-18/elt-6, one of which is essential for vulval expression of egl-18/elt-6 reporter constructs. These findings demonstrate that the EGL-18 and ELT-6 GATA factors are essential, genetically redundant regulators of cell fates and fusion in the developing vulva and are apparent direct transcriptional targets of the LIN-39 Hox protein.

eng

IM

MEDLINE

0950-1991

Print

NLM

5171-80

pubmed-meshheading:12399309-Animals, pubmed-meshheading:12399309-Binding Sites, pubmed-meshheading:12399309-Caenorhabditis elegans, pubmed-meshheading:12399309-Caenorhabditis elegans Proteins, pubmed-meshheading:12399309-Cell Differentiation, pubmed-meshheading:12399309-Cell Fusion, pubmed-meshheading:12399309-DNA-Binding Proteins, pubmed-meshheading:12399309-Dimerization, pubmed-meshheading:12399309-Enhancer Elements, Genetic, pubmed-meshheading:12399309-Female, pubmed-meshheading:12399309-GATA Transcription Factors, pubmed-meshheading:12399309-Green Fluorescent Proteins, pubmed-meshheading:12399309-Helminth Proteins, pubmed-meshheading:12399309-Homeodomain Proteins, pubmed-meshheading:12399309-Luminescent Proteins, pubmed-meshheading:12399309-Mutation, pubmed-meshheading:12399309-Neurons, pubmed-meshheading:12399309-Recombinant Proteins, pubmed-meshheading:12399309-Transcription Factors, pubmed-meshheading:12399309-Vulva

Cell fates and fusion in the C. elegans vulval primordium are regulated by the EGL-18 and ELT-6 GATA factors -- apparent direct targets of the LIN-39 Hox protein.

Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't