Senthilkumaran B, Sudhakumari C C, Wang D S, Sreenivasulu G, Kobayashi T, Kobayashi H-K, Yoshikuni M, Nagahama Y
Laboratory of Reproductive Biology, National Institute for Basic Biology, Myodaiji, Okazaki 444-8585, Japan.
Mol Cell Endocrinol. 2009 Feb 27;299(2):146-52. doi: 10.1016/j.mce.2008.11.008. Epub 2008 Nov 18.
Multiple forms of 3beta-hydroxysteroid dehydrogenase/isomerase (3beta-HSD) and their differential tissue expression pattern have not been shown in any lower vertebrates. In the present study, we report cloning of two novel 3beta-HSDs and two variants from gonads of the Nile tilapia. 3beta-HSD cDNAs encode two peptides of 375 (3beta-HSD type-I/variant 1) and 367 (3beta-HSD type-II/variant 1) amino acid residues that share 31.9% homology. 3beta-HSD type-I/variant 1 shared high homology with other piscine counterparts while 3beta-HSD type-II/variant 1 exhibited homology to mammalian DeltaC27-3beta-HSD and multifunctional viral 3beta-HSD. The latter seems to be ancient form among vertebrates. Transiently transfected 3beta-HSDs' open reading frames in COS-7 cells converted exogenous pregnenolone/androsta-5-ene-3beta-17beta-diol to progesterone/testosterone. Tissue distribution pattern of 3beta-HSDs by RT-PCR revealed varied expression pattern. Northern blot analysis of 3beta-HSDs demonstrated steady or gradual rise in transcripts level at different gonadal stages. These data revealed the importance of novel 3beta-HSDs in teleosts and also provided phylogenetic significance.
多种形式的3β-羟基类固醇脱氢酶/异构酶（3β-HSD）及其不同的组织表达模式在任何低等脊椎动物中均未被发现。在本研究中，我们报告了从尼罗罗非鱼性腺中克隆出两种新型3β-HSD和两种变体。3β-HSD cDNA编码两个分别含有375个（3β-HSD I型/变体1）和367个（3β-HSD II型/变体1）氨基酸残基的肽段，它们具有31.9%的同源性。3β-HSD I型/变体1与其他鱼类的对应物具有高度同源性，而3β-HSD II型/变体1与哺乳动物的DeltaC27-3β-HSD和多功能病毒3β-HSD具有同源性。后者似乎是脊椎动物中的古老形式。在COS-7细胞中瞬时转染3β-HSD的开放阅读框可将外源性孕烯醇酮/雄甾-5-烯-3β-17β-二醇转化为孕酮/睾酮。通过RT-PCR分析3β-HSD的组织分布模式显示出不同的表达模式。对3β-HSD进行Northern印迹分析表明，在不同性腺阶段转录本水平稳定或逐渐升高。这些数据揭示了新型3β-HSD在硬骨鱼中的重要性，也提供了系统发育意义。
