HSP90α Gene Expression May Be a Conserved Feature of Vertebrate Somitogenesis

Abstract

We have previously demonstrated that thehsp90α andhsp90β genes in zebrafish are expressed in dramatically different spatial and temporal patterns in early embryos. In the case ofhsp90α, expression is spatially restricted within the somites to putative myogenic cells which also express mRNA encoding the myogenic bHLH transcription factor myoD and is downregulated along withmyoDfollowing myogenesis. In the present study, we have examinedhsp90α gene expression in developing chicken embryos using a gene-specific probe. We show thathsp90α gene expression is also localized to a subset of cells within the somites of chicken embryos and that the expression pattern correlates closely to that observed formyoD.Furthermore, expression of thehsp90α gene is strongly upregulated throughout the embryo following heat shock in a manner similar to that observed in heat-shocked zebrafish embryos. The data suggest that thehsp90α gene may play an evolutionarily conserved role during somitogenesis in vertebrates in addition to providing protection to all cells of the embryo following stress.