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Published January 15, 1997 | public
Journal Article

SpHmx, a Sea Urchin Homeobox Gene Expressed in Embryonic Pigment Cells

Abstract

We describe the first complete sea urchin member of the H6 subfamily of homeobox genes. A cDNA encoding the complete protein was recovered from a Strongylocentrotus purpuratus library, and sequence comparisons demonstrate that this gene belongs to the same family as the Nkx-5.1, Nkx-5.2, and H6 genes of mammals, and the GH6 and SOHo-1 genes of chicken. In accord with current nomenclature this gene is named SpHmx. The gene is present in a single copy per haploid genome. Single-strand probe excess hybridization demonstrates that a rare maternal SpHmx mRNA is present in unfertilized eggs. Strong zygotic expression begins during the blastula stage, and the transcript is present at moderately high levels until late in development. Whole mountin situhybridization reveals a remarkable pattern of expression: In midgastrula-stage embryos SpHmx is expressed throughout the archenteron, but particularly strongly in delaminating secondary mesenchyme cells. This more general expression resolves to a dramatic pigment cell-specific pattern in prism and pluteus stages. SpHmx apparently encodes a cell-type-specific transcription factor of embryonic pigment cells.

Additional Information

© 1997 Academic Press. Available online 2 May 2002. The authors thank Drs.Carmen Kirchhamer andMaria I. Arnone for their help with the wholemount in situ hybridizations and Drs. Leonard Bogarad and R. Andrew Cameron for their comments on the manuscript. We are particularly appreciative of the generosity of Dr. Donna Livant for making her pigment cell-enriched DNA preparation available to us. This work was supported by a grant from the National Institutes of Health (HD 05753).

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023