Xtr, a plural tudor domain-containing protein, is involved in the translational regulation of maternal mRNA during oocyte maturation in Xenopus laevis.
Xtr, a plural tudor domain-containing protein, is involved in the translational regulation of maternal mRNA during oocyte maturation in Xenopus laevis.
复制标题
Xtr 是一种含有多个 tudor 结构域的蛋白质，参与非洲爪蟾卵母细胞成熟过程中母体 mRNA 的翻译调节。
DOI：
10.1111/j.1440-169x.2012.01367.x
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Takamune K.
中科院分区：
文献类型：
--
作者：
Ohgami H;Hiyoshi M;Mostafa MG;Kubo H;Abe S;Takamune K.
Xenopus受精卵中的Xtr已被证明是信使核糖核蛋白（mRNP）复合体的一员，在卵裂过程中的核分裂中起着至关重要的作用。由于Xtr也存在于卵母细胞和精母细胞中，并且其量在精子发生细胞进入减数分裂期后立即增加，因此预测该蛋白质也在减数分裂进行期间起作用。利用异种卵母细胞体积大的优势，通过微量注射抗Xtr抗体来抑制Xtr的功能，我们研究了Xtr在卵母细胞减数分裂过程中的作用。将抗Xtr抗体显微注射到未成熟卵母细胞中，然后重新启动卵母细胞成熟，不会影响减数分裂进程中的生发泡破裂和Cdc 2/细胞周期蛋白B活性的振荡，但会导致减数分裂中期I和II的异常纺锤体形成和染色体排列。Xtr的免疫沉淀显示Xtr与FRGY 2和mRNA如RCC 1和XL-INCENP mRNA相关，这些mRNA参与有核分裂的进展。当将抗Xtr抗体注射到卵母细胞中时，即使卵母细胞用孕酮处理，已知在未成熟卵母细胞中被抑制并在卵母细胞成熟重新开始后被诱导的XL‐INCENP mRNA的翻译也被抑制。在注射报告基因mRNA的卵母细胞中观察到类似的翻译调控，该报告基因mRNA由增强的绿色荧光蛋白开放阅读框和XL‐INCENP mRNA的3′非翻译区（3′UTR）组成。这些结果表明，Xtr在卵母细胞减数分裂过程中通过其3′UTR调节XL‐INCENP mRNA的翻译。
Xtr in the fertilized eggs ofXenopushas been demonstrated to be a member of a messenger ribonucleoprotein (mRNP) complex that plays a crucial role in karyokinesis during cleavage. Since the Xtr is also present both in oocytes and spermatocytes and its amount increases immediately after spematogenic cells enter into the meiotic phase, this protein was also predicted to act during meiotic progression. Taking advantage ofXenopusoocytes’ large size to microinject anti‐Xtr antibody into them for inhibition of Xtr function, we examined the role of Xtr in meiotic progression of oocytes. Microinjection of anti‐Xtr antibody into immature oocytes followed by reinitiation of oocyte maturation did not affect germinal vesicle break down and the oscillation of Cdc2/cyclin B activity during meiotic progression but caused abnormal spindle formation and chromosomal alignment at meiotic metaphase I and II. Immunoprecipitation of Xtr showed the association of Xtr with FRGY2 and mRNAs such as RCC1 and XL‐INCENP mRNAs, which are involved in the progression of karyokinesis. When anti‐Xtr antibody was injected into oocytes, translation of XL‐INCENP mRNA, which is known to be repressed in immature oocytes and induced after reinitiation of oocyte maturation, was inhibited even if the oocytes were treated with progesterone. A similar translational regulation was observed in oocytes injected with a reporter mRNA, which was composed of an enhanced green fluorescent protein open reading frame followed by the 3′ untranslational region (3′UTR) of XL‐INCENP mRNA. These results indicate that Xtr regulates the translation of XL‐INCENP mRNA through its 3′UTR during meiotic progression of oocyte.