Fang H, Brandhorst B P
Institute of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby B.C., Canada.
Dev Biol. 1996 Jan 10;173(1):306-17. doi: 10.1006/dbio.1996.0025.
The genome of the sea urchin Lytechinus pictus includes genes encoding four cytoskeletal actins LpC1-4 and the muscle actin LpM. Gene-specific probes corresponding to 3' noncoding termini have been used to characterize their patterns of expression by in situ hybridization. The gene encoding LpC1 actin, which is most similar in sequence to the Strongylocentrotus purpuratus CyI actin, has a complex developmental profile of expression. LpC1 transcripts become prominent in the archenteron and secondary mesenchyme cells of embryos, as well as in adult testis and ovary. The LpC2 actin gene is predominantly expressed in aboral ectoderm of embryos, similarly to the pattern of expression of its closest relatives in S. purpuratus, the SpCyIIIa and SpCyIIIb actin genes. The LpC3 actin gene is expressed at low levels in secondary mesenchyme cells. The LpC4 actin gene is expressed in a subset of primary mesenchyme cells which may be actively engaged in skeletogenesis. Transcripts of the LpM gene accumulate in esophageal muscle cells beginning during gastrulation before overt differentiation. Each of the L. pictus actin genes has a distinct pattern of expression, none of which is identical to that of any S. purpuratus actin gene. These results indicate that the regulation of expression of members of the actin gene family, even those likely to have common ancestors, has diverged as these sea urchin species diverged.
海胆（Lytechinus pictus）的基因组包含编码四种细胞骨架肌动蛋白LpC1 - 4和肌肉肌动蛋白LpM的基因。对应于3'非编码末端的基因特异性探针已被用于通过原位杂交来表征它们的表达模式。编码LpC1肌动蛋白的基因，其序列与紫球海胆（Strongylocentrotus purpuratus）的CyI肌动蛋白最为相似，具有复杂的发育表达谱。LpC1转录本在胚胎的原肠和次级间充质细胞以及成年睾丸和卵巢中变得显著。LpC2肌动蛋白基因主要在胚胎的反口外胚层中表达，类似于其在紫球海胆中最接近的亲属SpCyIIIa和SpCyIIIb肌动蛋白基因的表达模式。LpC3肌动蛋白基因在次级间充质细胞中低水平表达。LpC4肌动蛋白基因在可能积极参与骨骼形成的初级间充质细胞亚群中表达。LpM基因的转录本在原肠胚形成期间、在明显分化之前开始在食管肌肉细胞中积累。海胆（Lytechinus pictus）的每个肌动蛋白基因都有独特的表达模式，其中没有一个与任何紫球海胆肌动蛋白基因的表达模式相同。这些结果表明，即使是那些可能有共同祖先的肌动蛋白基因家族成员的表达调控，也随着这些海胆物种的分化而发生了分歧。
