Expression of stimulated by retinoic acid gene 8 (Stra8) and maturation of murine gonocytes and spermatogonia induced by retinoic acid in vitro
Expression of stimulated by retinoic acid gene 8 (Stra8) and maturation of murine gonocytes and spermatogonia induced by retinoic acid in vitro
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DOI：
10.1095/biolreprod.107.064337
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发表时间：
2008-03-01
影响因子：
3.6
通讯作者：
Griswold, Michael D.
中科院分区：
文献类型：
--
作者：
Zhou, Qing;Li, Ying;Griswold, Michael D.
小鼠缺乏维生素A会导致未分化精原细胞向分化精原细胞分化的进程受阻。维生素A缺乏的小鼠补充视黄醇会在整个睾丸中以同步方式重新启动精子发生。目前尚不清楚维甲酸的作用是直接作用于生殖细胞还是通过支持细胞间接调节。维甲酸基因8(Stra8)是精子发生所必需的基因，其表达水平与维甲酸(RA)的可利用性直接相关。基因芯片分析显示，STRA8基因在性细胞中有中等水平的转录，在A和B精原细胞中有高水平的表达。在生殖细胞中，一旦进入减数分裂，Stra8的mRNA水平就会大大降低或缺失。本研究观察了维甲酸对体外培养的新生儿睾丸和分离的生殖细胞/精原细胞的影响。用磁激活细胞分选法从不同月龄小鼠的睾丸中分离出THY1(+)和KIT+生殖细胞。分离的生殖细胞用无饲养层细胞的溶剂(乙醇)或维甲酸处理。我们发现：1)Stra8主要在减数分裂前生殖细胞中表达，2)RA刺激培养的新生睾丸生殖细胞DNA复制和分化，3)在没有饲养细胞的情况下，RA通过刺激Stra8和Kit基因的表达直接诱导未分化的精原细胞向分化的精原细胞转变，4)RA显著地刺激未分化的精原细胞的Stra8的表达，但对精原细胞的分化影响较小，5)内源性的Stra8基因在分化的精原细胞中的表达高于在未分化的精原细胞中的表达，并可能介导RA对精原细胞成熟的影响，以及6)RA刺激一组与维甲酸的代谢、储存、运输和信号传递有关的基因。
Vitamin A deficiency in the mouse results in an arrest in the progression of undifferentiated spermatogonia to differentiating spermatogonia. The supplement of retinol to vitamin-A-deficient mice reinitiates spermatogenesis in a synchronous manner throughout the testes. It is unclear whether the effects of retinoids are the result of a direct action on germ cells or are indirectly mediated through Sertoli cells. The expression of Stimulated by retinoic acid gene 8 (Stra8), which is required for spermatogenesis, is directly related to the availability of retinoic acid (RA). Analysis of gene expression by microarrays revealed moderate levels of Stra8 transcript in gonocytes and high levels in A and B spermatogonia. Stra8 mRNA levels were greatly reduced or absent in germ cells once they entered meiosis. This study examined the effect of retinoic acid on cultured neonatal testes and isolated gonocytes/spermatogonia in vitro. THY1(+) and KIT+ germ cells were isolated by magnetic-activated cell sorting from the testes of mice of different ages. Isolated germ cells were cultured and treated with either vehicle (ethanol) or RA without feeder cells. We found that 1) Stra8 is predominantly expressed in premeiotic germ cells, 2) RA stimulates gonocyte DNA replication and differentiation in cultured neonatal testes, 3) in the absence of feeder cells, RA directly induces the transition of undifferentiated spermatogonia to differentiating spermatogonia by stimulating Stra8 and Kit gene expression, 4) RA dramatically stimulates Stra8 expression in undifferentiated spermatogonia but has a lesser impact in differentiating spermatogonia, 5) endogenous Stra8 gene expression is higher in differentiating spermatogonia than in undifferentiated spermatogonia and could mediate the RA effects on spermatogonial maturation, and 6) RA stimulates a group of genes involved in the metabolism, storage, transport, and signaling of retinoids.