MED GATA factors promote robust development of the C. elegans endoderm

Dev Biol. 2015 Aug 1;404(1):66-79. doi: 10.1016/j.ydbio.2015.04.025. Epub 2015 May 8.


The MED-1,2 GATA factors contribute to specification of E, the progenitor of the Caenorhabditis elegans endoderm, through the genes end-1 and end-3, and in parallel with the maternal factors SKN-1, POP-1 and PAL-1. END-1,3 activate elt-2 and elt-7 to initiate a program of intestinal development, which is maintained by positive autoregulation. Here, we advance the understanding of MED-1,2 in E specification. We find that expression of end-1 and end-3 is greatly reduced in med-1,2(-) embryos. We generated strains in which MED sites have been mutated in end-1 and end-3. Without MED input, gut specification relies primarily on POP-1 and PAL-1. 25% of embryos fail to make intestine, while those that do display abnormal numbers of gut cells due to a delayed and stochastic acquisition of intestine fate. Surviving adults exhibit phenotypes consistent with a primary defect in the intestine. Our results establish that MED-1,2 provide robustness to endoderm specification through end-1 and end-3, and reveal that gut differentiation may be more directly linked to specification than previously appreciated. The results argue against an "all-or-none" description of cell specification, and suggest that activation of tissue-specific master regulators, even when expression of these is maintained by positive autoregulation, does not guarantee proper function of differentiated cells.

Keywords: C. elegans; Cell specification; Endoderm; GATA factors; Gene regulation; Gene regulatory networks; Robustness.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans Proteins / metabolism*
  • Endoderm / cytology
  • Endoderm / metabolism
  • GATA Transcription Factors / metabolism*
  • Intestinal Mucosa / metabolism
  • Intestines / embryology
  • Transcription Factors / metabolism


  • Caenorhabditis elegans Proteins
  • END-1 protein, C elegans
  • END-3 protein, C elegans
  • GATA Transcription Factors
  • MED-1 protein, C elegans
  • MED-2 protein, C elegans
  • Transcription Factors