Rajapaksha W R, Robertson L, O'Shaughnessy P J
Department of Veterinary Physiology, University of Glasgow Veterinary School, Scotland, UK.
Mol Cell Endocrinol. 1996 Jun 18;120(1):25-30. doi: 10.1016/0303-7207(96)03816-6.
In cattle, as in many other species, formation of the corpus luteum is associated with loss of sensitivity to FSH. To determine whether this is associated with changes in FSH-receptor mRNA levels or alternate splicing of the primary transcript, reverse transcription and the polymerase chain reaction (RT-PCR) were used to examine transcripts during granulosa cell luteinization in vivo and in vitro. Using RT-PCR and Southern blotting, three alternate transcripts of the FSH-receptor were found consistently in bovine granulosa cells. The largest transcript encoded the full-length receptor while the other transcripts lacked either exon 9 or exons 4, 5 and 9. One day after luteinization in vivo, full-length FSH-receptor mRNA was detectable at low levels in the newly-formed corpus luteum. By day 3, however, no full-length transcripts were detectable in the corpus luteum. In contrast, when primers were used which amplify only the extracellular domain, FSH-receptor transcripts were detectable in all corpora lutea tested up to mid-cycle. In granulosa cells, luteinized in vitro, there was a similar loss of full-length FSH-receptor transcripts after day 1 but continued expression of transcripts encoding the extracellular domain. Results show that granulosa cell luteinization in cattle is associated with a change in splicing of the FSH-receptor primary transcript such that after luteinization only shortened transcripts coding for the extracellular domain are detectable. This process resembles, in reverse, changes in FSH-receptor transcript splicing during development of the gonads.
与许多其他物种一样，在牛中，黄体的形成与对促卵泡素（FSH）敏感性的丧失有关。为了确定这是否与FSH受体mRNA水平的变化或初级转录本的可变剪接有关，采用逆转录和聚合酶链反应（RT-PCR）来检测体内和体外颗粒细胞黄体化过程中的转录本。使用RT-PCR和Southern印迹法，在牛颗粒细胞中始终发现FSH受体的三种可变转录本。最大的转录本编码全长受体，而其他转录本则缺少外显子9或外显子4、5和9。在体内黄体化一天后，在新形成的黄体中可检测到低水平的全长FSH受体mRNA。然而，到第3天，在黄体中未检测到全长转录本。相比之下，当使用仅扩增细胞外结构域的引物时，在所有测试的黄体中直至周期中期都可检测到FSH受体转录本。在体外黄体化的颗粒细胞中，第1天后全长FSH受体转录本也有类似的减少，但编码细胞外结构域的转录本持续表达。结果表明，牛颗粒细胞黄体化与FSH受体初级转录本的剪接变化有关，即黄体化后仅可检测到编码细胞外结构域的缩短转录本。这个过程与性腺发育过程中FSH受体转录本剪接的变化相反。
