A Study on the Role of Arylsulfatase in Sea Urchin Development

在海胆胚胎发育过程中，在原肠形成开始之前的间叶囊胚期，芳基硫酸酯酶的活性开始急剧增加。本研究旨在阐明芳基硫酸酯酶在原肠形成过程中的作用。本项为期两年的研究结果如下：(1)克隆了海胆胚胎芳基硫酸酯酶(Ars)基因，并测定了其序列。(2)以ars-cDNA反义RNA为探针，进行原位杂交，发现ars基因仅在海胆原肠胚具反义外胚层中转录。(3)通过对芳基硫酸酯酶活性的光镜和电子显微镜染色，发现芳基硫酸酯酶定位于拟球囊幼虫、棱柱幼虫和海胆幼虫的溶酶体中。结果表明，芳基硫酸酯酶通过降解原肠发育所需的蛋黄物质提供硫酸盐离子。(4)在海胆胚胎中加入DNA合成抑制因子aphidiclin可抑制ars基因的转录。这一结果被解释为Ars基因转录的时间与受精后的DNA复制周期有关。

In development of sea urchin embryos, the arylsulfatase activity begins to make a drastic increase at the mesenchyme blastula stage prior to the onset of gastrulation. The present research project has been undertaken to elucidate roles of arylsulfatase in the process of gastrulation. The following are the result of the two-years research project.(1) The arylsulfatase (Ars) gene of the embryo of the sea urchin, Hemicentrotus pulcherrimus, was cloned and its sequence was determined.(2) By in situ hybridization using anti-sense RNA of Ars-cDNA as the probe, it was found that the Ars gene is transcribed only in aboral ectoderm of sea urchin gastrula.(3) By the activity staining of arylsulfatase with optical as well as electron microscopes, it was found that arylulfatase localizes in lysosomes of qastrula, prism and pluteus larvae. It is suggested that arylsulfatase supplies sulfate ions through hydrolysis of yolk material which are needed to support gastrulation.(4) Addition of aphidicolin, an inhibitor of DNA synthesis, to sea urchin embryos resulted in the prevention of transcription of the Ars gene. The result was interpreted as that timing of the Ars gene transcription is somehow related to cycles of DNA replication after fertilization.