Angerer L M, Chambers S A, Yang Q, Venkatesan M, Angerer R C, Simpson R T
Department of Biology, University of Rochester, New York 14627.
Genes Dev. 1988 Feb;2(2):239-46. doi: 10.1101/gad.2.2.239.
We have previously described cloning of an exon of a sea urchin collagen gene and shown that its expression is temporally regulated during embryogenesis, beginning during blastula formation. We have now localized the protein encoded by the gene and the sites of its mRNA synthesis in the developing embryo. Antibody to a synthetic peptide reacts with a 208,000 Mr protein that is digestible by collagenase. Fractionation of pluteus stage embryos demonstrates that the protein is localized primarily with cells that form the syncytium of primary mesenchyme that elaborates the larval endoskeleton; furthermore, immunofluorescence localizes the epitope to the periphery of the endoskeleton in situ. Transcripts of the gene accumulate only in mesenchyme cells, especially those of the primary mesenchyme lineage. Measurements of absolute transcript abundance show that collagen mRNA is present in blastula primary mesenchyme cells at 600-700 copies per cell and at about fourfold lower amounts in other mesenchyme cells.
我们之前描述过海胆胶原蛋白基因一个外显子的克隆，并表明其表达在胚胎发育过程中受到时间调控，始于囊胚形成期。我们现在已确定该基因编码的蛋白质及其mRNA在发育中胚胎的合成位点。针对合成肽的抗体与一种208,000道尔顿的蛋白质发生反应，该蛋白质可被胶原酶消化。对长腕幼虫期胚胎进行分级分离表明，该蛋白质主要定位于形成构建幼虫内骨骼的初级间充质细胞合体的细胞中；此外，免疫荧光将表位原位定位在内骨骼的周边。该基因的转录本仅在间充质细胞中积累，尤其是初级间充质谱系的细胞。绝对转录本丰度的测量表明，囊胚初级间充质细胞中胶原mRNA的含量为每个细胞600 - 700个拷贝，在其他间充质细胞中的含量约低四倍。
