Feng H C, Bhave M, Fairclough R J
Centre For Bioprocessing and Food Technology, Victoria University of Technology, PO Box 14428, MCMC Melbourne, Victoria 8001 Australia.
J Reprod Fertil. 2000 Sep;120(1):187-200.
The increase in uterine oxytocin receptor concentrations over the late luteal phase of the oestrous cycle in sheep is thought to play an important role in the regulation of the duration of the cycle by facilitating the effect of oxytocin on uterine prostaglandin release. Experiments indicated that oxytocin receptor mRNA expression in the endometrium was high at oestrus compared with at days 2, 7 and 12 of the oestrous cycle. The amount of oxytocin receptor mRNA expression in the pituitary gland did not show any significant differences during the oestrous cycle. Oxytocin receptor cDNA was obtained and characterized from ovine uterine endometrium on day 15 of the oestrous cycle, using RT-PCR techniques, to study the mechanisms underlying the resolution of oxytocin receptor expression. The cDNA sequence for the oxytocin receptor gene in sheep was found to be similar to that described previously, except for a difference of seven nucleotides. These nucleotide differences resulted in changes in four of the deduced amino acids in the oxytocin receptor sequence. The heterogeneity of the different sized oxytocin receptor transcripts in sheep is due, at least in part, to the alternative use of polyadenylation sites. Northern hybridization confirmed that the oxytocin receptor gene is expressed in ovine corpus luteum. The investigations on oxytocin receptor gene expression indicate that the patten of oxytocin receptor gene expression in sheep is not only tissue-specific, but also highly function-related. Evidence was obtained of mRNA editing in both the coding and the 3'-untranslated (3'UTR) regions of oxytocin receptor gene transcripts in ovine endometrium; this was the first demonstration of this phenomenon for oxytocin receptor mRNA. The present results indicate that the observed differences in oxytocin receptor mRNA sequences for the different oxytocin receptor populations in endometrium are due to mRNA editing. mRNA editing of oxytocin receptor transcripts may be reflected in changes in the amino acid composition of the carboxyl terminus of the receptor, which would explain the differences in the observed responses to an oxytocin challenge.
绵羊发情周期黄体后期子宫催产素受体浓度的增加，被认为通过促进催产素对子宫前列腺素释放的作用，在调节周期持续时间方面发挥重要作用。实验表明，与发情周期的第2、7和12天相比，发情时子宫内膜中催产素受体mRNA的表达较高。垂体中催产素受体mRNA的表达量在发情周期中未显示出任何显著差异。利用逆转录聚合酶链反应（RT-PCR）技术，从发情周期第15天的绵羊子宫子宫内膜中获得并鉴定了催产素受体cDNA，以研究催产素受体表达解析的潜在机制。发现绵羊催产素受体基因的cDNA序列与先前描述的相似，但有七个核苷酸的差异。这些核苷酸差异导致催产素受体序列中四个推导氨基酸的变化。绵羊中不同大小的催产素受体转录本的异质性至少部分归因于聚腺苷酸化位点的交替使用。Northern杂交证实催产素受体基因在绵羊黄体中表达。对催产素受体基因表达的研究表明，绵羊中催产素受体基因的表达模式不仅具有组织特异性，而且与功能高度相关。在绵羊子宫内膜中，催产素受体基因转录本的编码区和3'-非翻译区（3'UTR）均获得了mRNA编辑的证据；这是催产素受体mRNA这种现象的首次证明。目前的结果表明，子宫内膜中不同催产素受体群体的催产素受体mRNA序列中观察到的差异是由于mRNA编辑。催产素受体转录本的mRNA编辑可能反映在受体羧基末端氨基酸组成的变化上，这可以解释观察到的对催产素刺激反应的差异。
