p21活化蛋白激酶2（PAK2）在生物中具有促进细胞增殖生长、抗凋亡等重要作用，可激活细胞增殖生长相关基因的表达。为探究PAK2基因在石磺细胞增殖代谢中的作用，通过RACE技术克隆得到瘤背石磺 (Onchidium reevesii)PAK2基因的cDNA全长，并利用实时荧光定量PCR(qRT-PCR)技术分析PAK2基因在不同组织中的相对表达情况。结果表明，瘤背石磺PAK2基因cDNA全长1 809 bp，包含1 488 bp的开放阅读框，共编码495个氨基酸，基因序列较为保守。序列分析结果显示，瘤背石磺和光滑双脐螺（Biomphalaria glabrata）PAK2基因相似度达到83%，氨基酸序列同源性高达88％。通过生物进化分析研究得出瘤背石磺与绿色海蜗牛（Elysia chlorotica）的进化关系相对较近。qRT-PCR结果显示，肠道和背部PAK2基因表达量明显高于其他组织，其次为神经组织和肝胰腺，腹足、口器和性腺的表达量处于中等水平，而蛋白腺表达最低。初步阐明了瘤背石磺PAK2基因的生物信息学特征以及在各组织中的表达水平，为研究其在石磺科贝类中的具体作用机理奠定了基础。
Previous studies have shown that p21 activated protein kinase 2 (PAK2) plays an important role in promoting cell proliferation and anti-apoptosis in organisms, and can activate the expression of genes related to cell proliferation and growth. In order to explore the role of p21 activated protein kinase 2 (PAK2) gene in the proliferation and metabolism of histocyte of Onchidium reevesii, the cDNA of O.r- PAK2 gene was cloned by RACE technology, and the corresponding tissue expression was analyzed by real-time quantitative PCR(qRT-PCR). The results showed that the total length of cDNA of PAK2 was 1 809 base pairs(bp), comprising a 183 bp 5’ untranslated region (UTR), a 138 bp 3’UTR, and 1 488 bp open reading frame (ORF)which encodes 495 amino acids. Based on the homology analysis of amino acid sequences, the similarity of PAK2 gene between O. reevesii and Biomphalaria glabrata was up to 83%, with a homology of 88%. O. reevesii is related to the evolution of Elysia chlorotica. qRT-PCR results showed that PAK2 gene was expressed in all tissues. The expression level of intestinal tract and back was significantly higher than that of other tissues, followed by nerve tissue and hepatopancreas. The expression level of protein gland was the lowest, and the expression level of abdominal foot and mouth organ was at the medium level. In this study, the bioinformatics characteristics and expression levels of PAK2 gene in various tissues were preliminarily clarified. The study laid the foundation for specific action mechanism of shellfish.