中文摘要：

采用RT-PCR、RACE等方法，获得了拟穴青蟹PP2A调节亚基B（PP2A-B）的cDNA全序列，全长2040bp，开放阅读框（0RF）为1332bp，可编码443个氨基酸残基。同源分析显示，该基因编码的蛋白与其它一些物种具有很高相似性，推测PP2A-B基因具有很高的保守性。经荧光定量PCR检测，PP2A-B基因在拟穴青蟹多个组织中有表达，且在脑、卵巢、鳃中表达量较高。在拟穴青蟹卵巢发育过程中，PP2A-B基因在卵巢未发育期（I期）表达量最高，此后各期逐渐下降，推测PP2A-B在卵巢中可能以PP2A全酶的形式存在，抑制卵巢发育。

英文摘要：

In this paper, the regulatory subunit B gene of PP2A （PP2A-B） was isolated from the mud crab, Scylla pa- ramamosain using RT-PCR and RACE methods. The obtained full-length cDNA of PP2A-B was 2040bp with an open reading frame of 1332bp encoding a putative peptide of 443 amino acid. By alignment, the amino acid sequence of S. pa- ramamosain PP2A-B showed high homology with those of some other animals. It suggested PP2A-B was highly conserva- tive. Real-time PCR showed that the PP2A-B gene was expressed in various tissues, and highly expressed in brain, ovary and gill. The PP2A-B mRNA expression during ovarian development indicated that the expression of PP2A-B was obvi- ously high at undeveloped stage and decreased gradually from stage I （undeveloped stage） to stage V （ripe stage）. We hy- pothesized that PP2A-B may exist in the form of PP2A holoenzyme in ovary and play a suppressive role on the ovarian development of the mud crab.