Ketola I, Rahman N, Toppari J, Bielinska M, Porter-Tinge S B, Tapanainen J S, Huhtaniemi I T, Wilson D B, Heikinheimo M
Children's Hospital, University of Helsinki, Finland.
Endocrinology. 1999 Mar;140(3):1470-80. doi: 10.1210/endo.140.3.6587.
Previous studies have shown that transcription factors GATA-4 and GATA-6 are expressed in granulosa and thecal cells of the mouse ovary and that GATA-4 expression in ovarian tissue is regulated by gonadotropins. Given the emerging role of GATA-4 and GATA-6 in gonadal cells, we have now studied the expression and regulation of these factors in the mouse testis and testicular cell lines. In situ hybridization demonstrated GATA-4 messenger RNA (mRNA) in the fetal testis at 13.5 days postcoitum. Both GATA-4 and GATA-6 transcripts were observed in late fetal, neonatal, juvenile, and adult Sertoli cells. In addition, GATA-4 mRNA was detected in interstitial cells throughout development. Immunohistochemistry demonstrated GATA-4 protein in both Sertoli and Leydig cells in postnatal animals. The regulation of GATA-4 and GATA-6 expression was explored using established testicular cell lines. Treatment of Leydig tumor cell lines with hCG resulted in a modest, but statistically significant, increase in the steady state level of GATA-4 mRNA, comparable to the previously described effect of FSH on GATA-4 expression in Sertoli cell lines. Gonadotropin or androgen action was not, however, a prerequisite for the basal expression of GATA-4 or GATA-6 in the testis, as their presence in Sertoli and Leydig cells was demonstrated in genetically hypogonadal hpg mice, in rats treated with GnRH receptor antagonist, and in Sertoli cells after chemical abolition of Leydig cells. Cotransfection studies using a GATA-4 expression plasmid and an inhibin alpha promoter/reporter gene construct in Leydig and granulosa tumor cell lines revealed that the inhibin alpha promoter harboring essential GATA-binding sites can be trans-activated by GATA-4. In light of these results, we propose that transcription factors GATA-4 and GATA-6 play differing roles in the maturation and function of testicular somatic cells.
先前的研究表明，转录因子GATA-4和GATA-6在小鼠卵巢的颗粒细胞和卵泡膜细胞中表达，并且卵巢组织中GATA-4的表达受促性腺激素调节。鉴于GATA-4和GATA-6在性腺细胞中日益凸显的作用，我们现在研究了这些因子在小鼠睾丸及睾丸细胞系中的表达和调节。原位杂交显示，在妊娠13.5天的胎儿睾丸中存在GATA-4信使核糖核酸（mRNA）。在胎儿晚期、新生儿期、幼年和成年的支持细胞中均观察到了GATA-4和GATA-6转录本。此外，在整个发育过程中的间质细胞中均检测到了GATA-4 mRNA。免疫组织化学显示，出生后动物的支持细胞和间质细胞中均有GATA-4蛋白。利用已建立的睾丸细胞系探索了GATA-4和GATA-6表达的调节。用人绒毛膜促性腺激素（hCG）处理间质细胞瘤细胞系，导致GATA-4 mRNA的稳态水平适度但有统计学意义地升高，这与先前描述的促卵泡激素（FSH）对支持细胞系中GATA-4表达的作用相当。然而，促性腺激素或雄激素的作用并非睾丸中GATA-4或GATA-6基础表达的先决条件，因为在遗传性性腺功能减退的hpg小鼠、用促性腺激素释放激素（GnRH）受体拮抗剂处理的大鼠以及化学去除间质细胞后的支持细胞中，均证实了它们在支持细胞和间质细胞中的存在。在间质瘤细胞系和颗粒细胞瘤细胞系中使用GATA-4表达质粒和抑制素α启动子/报告基因构建体进行共转染研究表明，含有必需GATA结合位点的抑制素α启动子可被GATA-4反式激活。鉴于这些结果，我们提出转录因子GATA-4和GATA-6在睾丸体细胞的成熟和功能中发挥不同作用。
