Brandhorst B P, Filion M, Nisson P E, Crain W R
Department of Biology, McGill University, Montreal, Canada.
Dev Biol. 1991 Apr;144(2):405-11. doi: 10.1016/0012-1606(91)90432-3.
Hybrid embryos were derived from reciprocal crosses of Strongylocentrotus purpuratus and Lytechinus pictus sea urchins. The expression of proteins specific for L. pictus was restricted in these hybrid embryos, while this was not so for most proteins specific for S. purpuratus. In particular, the aboral ectoderm-specific calcium-binding protein Spec1 was expressed at normal levels in hybrid embryos, but its L. pictus homologue, LpS1, was considerably reduced. LpS1 mRNA accumulated in hybrid plutei to only 4-5% of its normal level. Transcription of the LpS1 gene was substantially reduced in hybrid embryos, as determined by a nuclear RNA run-on assay. Southern blot analysis of genomic DNA indicated that there was no detectable loss or rearrangement of LpS1 DNA in hybrid embryos. Thus, the Spec1 gene is expressed normally in hybrid embryos, but the transcription of its homologue, the LpS1 gene, is considerably restricted.
杂交胚胎源自紫球海胆（Strongylocentrotus purpuratus）和花斑海胆（Lytechinus pictus）的正反交。在这些杂交胚胎中，花斑海胆特异蛋白的表达受到限制，而对于大多数紫球海胆特异蛋白而言并非如此。特别地，口反 ectoderm 特异性钙结合蛋白 Spec1 在杂交胚胎中以正常水平表达，但其花斑海胆同源物 LpS1 则大幅减少。LpS1 mRNA 在杂交长腕幼虫中积累至正常水平的仅 4 - 5%。通过核 RNA 延伸试验确定，杂交胚胎中 LpS1 基因的转录大幅减少。基因组 DNA 的 Southern 印迹分析表明，杂交胚胎中未检测到 LpS1 DNA 的缺失或重排。因此，Spec1 基因在杂交胚胎中正常表达，但其同源物 LpS1 基因的转录受到显著限制。
