Gomes Cynthia, Oh Sung-Dug, Kim Jung-Woo, Chun Sang-Young, Lee Keesook, Kwon Hyuk-Bang, Soh Jaemog
Hormone Research Center, Department of Molecular Endocrinology, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea.
Biol Reprod. 2005 Mar;72(3):651-8. doi: 10.1095/biolreprod.104.032672. Epub 2004 Nov 24.
Mammalian spermatogenesis is orchestrated by many specific molecular and cellular events. To understand the detailed mechanism by which spermatogenesis is controlled, the specific genes involved in this process must be identified and studied. From the subtracted cDNA library of rat testis prepared using the representational difference analysis (RDA) method, we isolated the cDNA clone of steroidogenic acute regulatory (StAR) protein-related lipid transfer (START) protein 6 (Stard6). Stard6 cDNA consists of 1146 base pairs of nucleotides and has the longest open reading frame, of 227 amino acids. Northern blot analysis revealed Stard6 mRNA to be testis-specific. The mRNA transcript appeared from the third week of postnatal development, and the expression level increased up to adulthood. Moreover, in situ hybridization showed Stard6 mRNA expression to be germ cell-specific and expressed only during the maturation stages of round and elongated spermatids of adult rat testis. Western blot analysis with Stard6 antibody revealed a 28-kDa Stard6 protein only in testis. Immunohistochemistry further confirmed localization of Stard6 protein expressed in mature germ cells, in concert with the in situ hybridization result. Taken together, these results suggest that Stard6, a member of the START protein family, may play a role during germ cell maturation in adult rat testis.
哺乳动物的精子发生由许多特定的分子和细胞事件精心调控。为了了解精子发生的详细调控机制，必须鉴定和研究参与这一过程的特定基因。利用代表性差异分析（RDA）方法构建大鼠睾丸消减cDNA文库，我们分离出了类固醇生成急性调节（StAR）蛋白相关脂质转运（START）蛋白6（Stard6）的cDNA克隆。Stard6 cDNA由1146个核苷酸碱基对组成，具有最长的开放阅读框，编码227个氨基酸。Northern印迹分析显示Stard6 mRNA具有睾丸特异性。该mRNA转录本在出生后第三周开始出现，表达水平在成年期持续升高。此外，原位杂交显示Stard6 mRNA表达具有生殖细胞特异性，且仅在成年大鼠睾丸圆形和长形精子细胞的成熟阶段表达。用Stard6抗体进行的Western印迹分析表明，仅在睾丸中存在一条28 kDa的Stard6蛋白条带。免疫组织化学进一步证实了Stard6蛋白在成熟生殖细胞中的定位，与原位杂交结果一致。综上所述，这些结果表明，作为START蛋白家族的一员，Stard6可能在成年大鼠睾丸生殖细胞成熟过程中发挥作用。
