The GATA-factor elt-2 is essential for formation of the Caenorhabditis elegans intestine.
The Caenorhabditis elegans elt-2 gene encodes a single-finger GATA factor, previously cloned by virtue of its binding to a tandem pair of GATA sites that control the gut-specific ges-1 esterase gene. In the present paper, we show that elt-2 expression is completely gut specific, beginning when the embryonic gut has only two cells (one cell cycle prior to ges-1 expression) and continuing in every cell of the gut throughout the life of the worm. When elt-2 is expressed ectopically using a transgenic heat-shock construct, the endogenous ges-1 gene is now expressed in most if not all cells of the embryo; several other gut markers (including a transgenic elt-2-promoter::lacZ reporter construct designed to test for elt-2 autoregulation) are also expressed ectopically in the same experiment. These effects are specific in that two other C. elegans GATA factors (elt-1 and elt-3) do not cause ectopic gut gene expression. An imprecise transposon excision was identified that removes the entire elt-2 coding region. Homozygous elt-2 null mutants die at the L1 larval stage with an apparent malformation or degeneration of gut cells. Although the loss of elt-2 function has major consequences for later gut morphogenesis and function, mutant embryos still express ges-1. We suggest that elt-2 is part of a redundant network of genes that controls embryonic gut development; other factors may be able to compensate for elt-2 loss in the earlier stages of gut development but not in later stages. We discuss whether elements of this regulatory network may be conserved in all metazoa.
Fukushige
T
T
Department of Biochemistry and Molecular Biology, University of Calgary, Alberta, Canada.
Hawkins
M G
MG
McGhee
J D
JD
D000818:Animals; D001757:Blastomeres / Q000502:physiology; D017173:Caenorhabditis elegans / Q000196:embryology*; D029742:Caenorhabditis elegans Proteins; D002265:Carboxylic Ester Hydrolases / Q000502:physiology; D050980:GATA Transcription Factors; D007422:Intestines / Q000196:embryology*; D009154:Mutation; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D016335:Zinc Fingers
D029742:Caenorhabditis elegans Proteins; C094134:ELT-2 protein, C elegans; D050980:GATA Transcription Factors; D014157:Transcription Factors; D002265:Carboxylic Ester Hydrolases; C095990:ges-1 protein, C elegans