A spatially dynamic cohort of regulatory genes in the endomesodermal gene network of the sea urchin embryo

Dev Biol. 2008 Jan 15;313(2):863-75. doi: 10.1016/j.ydbio.2007.10.042. Epub 2007 Nov 9.

Abstract

A gene regulatory network subcircuit comprising the otx, wnt8, and blimp1 genes accounts for a moving torus of gene expression that sweeps concentrically across the vegetal domain of the sea urchin embryo. Here we confirm by mutation the inputs into the blimp1cis-regulatory module predicted by network analysis. Its essential design feature is that it includes both activation and autorepression sites. The wnt8 gene is functionally linked into the subcircuit in that cells receiving this ligand generate a beta-catenin/Tcf input required for blimp1 expression, while the wnt8 gene in turn requires a Blimp1 input. Their torus-like spatial expression patterns and gene regulatory analysis indicate that the genes even-skipped and hox11/13b are also entrained by this subcircuit. We verify the cis-regulatory inputs of even-skipped predicted by network analysis. These include activation by beta-catenin/Tcf and Blimp1, repression within the torus by Hox11/13b, and repression outside the torus by Tcf in the absence of Wnt8 signal input. Thus even-skipped and hox11/13b, along with blimp1 and wnt8, are members of a cohort of torus genes with similar regulatory inputs and similar, though slightly out-of-phase, expression patterns, which reflect differences in cis-regulatory design.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • DNA Mutational Analysis
  • Embryo, Nonmammalian
  • Endoderm / physiology*
  • Female
  • Gene Expression
  • Gene Regulatory Networks*
  • Genes, Regulator*
  • Green Fluorescent Proteins / metabolism
  • In Situ Hybridization
  • Mesoderm / physiology*
  • Microinjections
  • Models, Genetic
  • Oocytes
  • RNA, Messenger / metabolism
  • Sea Urchins / embryology
  • Sea Urchins / genetics*
  • Sequence Analysis, DNA

Substances

  • RNA, Messenger
  • Green Fluorescent Proteins