ZFIN ID: ZDB-PUB-001027-7
Antagonistic role of vega1 and bozozok/dharma homeobox genes in organizer formation
Kawahara, A., Wilm, T., Solnica-Krezel, L., and Dawid, I.B.
Date: 2000
Source: Proceedings of the National Academy of Sciences of the United States of America   97(22): 12121-12126 (Journal)
Registered Authors: Dawid, Igor B., Kawahara, Atsuo, Solnica-Krezel, Lilianna, Wilm, Thomas
Keywords: none
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Body Patterning*
  • Gene Expression Regulation, Developmental*
  • Homeodomain Proteins/chemistry
  • Homeodomain Proteins/genetics*
  • Molecular Sequence Data
  • Sequence Homology, Amino Acid
  • Zebrafish/genetics*
  • Zebrafish Proteins*
PubMed: 11050240 Full text @ Proc. Natl. Acad. Sci. USA
During zebrafish development, zygotic gene expression initiated at the midblastula transition converts maternal information on embryo polarity into a transcriptional read-out. Expression of a homeobox gene, vega1, is activated at midblastula transition in all blastomeres, but is down-regulated dorsally before gastrulation. Ubiquitous expression of vega1 is maintained in bozozok mutants, in which the dorsal-specific homeobox gene bozozok/dharma (boz/dha) is disrupted and organizer formation is impaired. Vega1 inhibits expression of boz/dha and organizer-specific genes, and causes ventralization resulting in a headless phenotype. In contrast, VP16-vega1, a fusion including the Vega1 homeodomain and VP16 activation domain, elicits ectopic expression of organizer genes and suppresses several aspects of the boz mutant phenotype. We propose that boz/dha-dependent down-regulation of vega1 in the dorsal region is an early essential step in organizer formation in zebrafish.