Translational regulation of a novel testis‐specific RNF4 transcript
Translational regulation of a novel testis‐specific RNF4 transcript
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DOI：
10.1002/mrd.10322
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发表时间：
2003-09
影响因子：
2.5
通讯作者：
Raffaela Pero;F. Lembo;P. Chieffi;G. Del Pozzo;M. Fedele;A. Fusco;C. Bruni;L. Chiariotti
中科院分区：
文献类型：
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作者：
Raffaela Pero;F. Lembo;P. Chieffi;G. Del Pozzo;M. Fedele;A. Fusco;C. Bruni;L. Chiariotti
环指蛋白SNURF/RNF 4是类固醇受体依赖性和基础转录的调节剂，在睾丸中以非常高的水平表达，在其他几种组织中以低得多的水平表达。在体细胞组织中，RNF 4基因表达为3 kb的转录本，而在小鼠睾丸中发现了另外一个较短的转录本（1.6 kb）。在小鼠生殖细胞中，RNF 4蛋白表达在精原细胞向精子细胞的进展过程中受到强烈调节，在精母细胞中达到峰值。3 kb转录本的表达与不同生殖细胞群体中的蛋白质水平相关。相反，1.6 kb的转录本在精子细胞中大量特异性表达，其中RNF 4蛋白以非常低的水平检测到。然后我们研究了这种差异背后可能的机制。引物延伸和RNA酶保护分析表明，1.6-和3.0-kb的转录本来自相同的启动子，编码相同的蛋白质，但3′ UTR不同。体外实验表明，RNF 4蛋白水平的调节不涉及蛋白降解。最后，多核糖体分析显示，只有一小部分睾丸特异性转录物参与翻译，从而为RNF 4 mRNA和蛋白水平的定量差异提供了可行的机制。目前的研究结果表明，RNF 4短转录本是很差的翻译，这表明这种机制可能是必要的正常精子发生。摩尔Reprod. Dev. 66：1-7，2003.© 2003 Wiley利斯公司
The RING‐finger protein SNURF/RNF4, a modulator of both steroid receptor dependent and basal transcription, is expressed at very high levels in testis and at much lower levels in several other tissues. In somatic tissues, the RNF4 gene is expressed as a 3‐kb transcript while an additional shorter sized transcript (1.6 kb) was found in mouse testis. In murine germ cells, RNF4 protein expression is strongly modulated during progression of spermatogonia to spermatids, with a peak in spermatocytes. The expression of 3‐kb transcript correlated with protein levels in the different germ cell populations. Conversely, the 1.6‐kb transcript was abundantly and specifically expressed in spermatids, in which RNF4 protein was detected at very low levels. We have then examined possible mechanisms underlying this discrepancy. Primer extension and RNase protection analyses demonstrated that the 1.6‐ and 3.0‐kb transcripts originate from the same promoter, encode for the same protein and differ in the 3′ UTR. In vitro assays showed that protein degradation is not involved in the regulation of RNF4 protein level. Finally, polysome analysis revealed that only a slight fraction of the testis‐specific transcript is engaged in translation, thus providing a feasible mechanism for the quantitative differences of RNF4 mRNA and protein levels. Present results demonstrate that RNF4 short transcript is poorly translated suggesting that this mechanism could be essential for normal spermatogenesis. Mol. Reprod. Dev. 66: 1–7, 2003. © 2003 Wiley‐Liss, Inc.