Highly restricted expression at the ectoderm-endoderm boundary of PIHbox 9, a sea urchin homeobox gene related to the human HB9 gene

Mech Dev. 1998 Jun;74(1-2):185-8. doi: 10.1016/s0925-4773(98)00064-1.


Characterisation of a sea urchin (P. lividus) homeobox gene PIHbox 9 is reported. The homeodomain of PIHbox9 is 95% identical to the homeodomain of the human HB9 gene, indicating that the two genes are highly related. Temporal expression analysis during sea urchin embryogenesis showed an absence of transcripts at early cleavage stages. At late gastrula stage, transcripts were barely detectable and reached the highest abundance at prism/early pluteus stages. By whole mount in situ hybridisation we observed a highly restricted expression in a few cells of the ectoderm-endoderm boundary of embryos at the prism stage. At pluteus stages, expression of PIHbox 9 was confined around the anus.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ectoderm / metabolism
  • Embryo, Nonmammalian / metabolism
  • Embryo, Nonmammalian / ultrastructure
  • Endoderm / metabolism
  • Gastrula / metabolism
  • Gene Expression Regulation, Developmental*
  • Homeodomain Proteins / biosynthesis*
  • Homeodomain Proteins / genetics
  • In Situ Hybridization
  • Sea Urchins / embryology
  • Sea Urchins / genetics*
  • Transcription Factors / biosynthesis*
  • Transcription Factors / genetics


  • Homeodomain Proteins
  • MNX1 protein, human
  • Transcription Factors