pha-4, an HNF-3 homolog, specifies pharyngeal organ identity in Caenorhabditis elegans.
To build complex organs, embryos have evolved mechanisms that integrate the development of cells unrelated to one another by cell type or ancestry. Here we show that the pha-4 locus establishes organ identity for the Caenorhabditis elegans pharynx. In pha-4 mutants, pharyngeal cells are transformed into ectoderm. Conversely, ectopic pha-4 expression produces excess pharyngeal cells. pha-4 encodes an HNF-3 homolog selectively expressed in the nascent digestive tract, including all pharynx precursors at the time they are restricted to a pharyngeal fate. We suggest that pha-4 is a key component of a transcription-based mechanism to endow cells with pharyngeal organ identity.
Horner
M A
MA
Huntsman Cancer Institute, Center for Children, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah 84112 USA.
Quintin
S
S
Domeier
M E
ME
Kimble
J
J
Labouesse
M
M
Mango
S E
SE
D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics*; D004268:DNA-Binding Proteins; D004064:Digestive System / Q000196:embryology; D051858:Forkhead Transcription Factors; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D017238:Genes, Helminth / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics; D010614:Pharynx / Q000196:embryology*; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
D004268:DNA-Binding Proteins; C477894:FOXI1 protein, human; C106349:FOXJ1 protein, human; D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors