Analysis of TATA-binding protein 2 (TBP2) and TBP expression suggests different roles for the two proteins in regulation of gene expression during oogenesis and early mouse development
Analysis of TATA-binding protein 2 (TBP2) and TBP expression suggests different roles for the two proteins in regulation of gene expression during oogenesis and early mouse development
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DOI：
10.1530/rep-06-0337
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发表时间：
2007-07-01
期刊：
影响因子：
3.8
通讯作者：
Tora, Laslo
中科院分区：
文献类型：
--
作者：
Gazdag, Emese;Rajkovic, Aleksandar;Tora, Laslo
配子发生是生殖细胞产生的过程，对生殖至关重要。在哺乳动物中，卵母细胞中存在的母体mRNA和蛋白质是确保发育进程所必需的，直到胚胎在受精后激活其基因组。众所周知，卵母细胞在卵母细胞生长过程中合成这些母体因子，然后经历一个静止的转录期，该转录期仅在受精后恢复。然而，在卵子发生过程中，调控转录调控和随后沉默的机制还没有很好地理解。在这里，我们研究了TATA结合蛋白（TBP）和相关蛋白TBP2（也称为TRF3，TBP相关因子3）在卵子发生和早期小鼠胚胎中的表达和定位。我们发现，TBP在卵泡形成开始时在卵母细胞中表达，但在卵母细胞发育的进一步阶段中检测不到，并且仅在受精后再次变得丰富。与TBP相反，我们发现TBP2在卵泡发生过程中在生长的卵母细胞中高度表达，在排卵后下降，并且在受精后的两细胞阶段几乎检测不到。TBP和TBP2的镜像定位特征表明这两种蛋白在卵母细胞发育过程中和小鼠早期胚胎中建立专门的基因表达程序中具有不同的作用。对卵母细胞特异性因子被敲除的突变小鼠卵巢的分析表明，TBP2是调节卵子发生转录控制的潜在候选者。此外，我们的研究结果与卵母细胞缺乏卵母细胞特异性的核伴侣nucleoplasmin 2表明，TBP2的功能可能与非凝聚染色质构象。
Gametogenesis, the process during which germ cells are generated is essential for reproduction. In mammals, maternal mRNA and proteins present in the oocyte are required to ensure the progression of development until the embryo activates its genome after fertilisation. It is well established that the oocyte synthesises these maternal factors during oocyte growth and then undergoes a quiescent transcriptional period that will be resumed only after fertilisation. However, the mechanisms that govern transcriptional regulation and subsequent silencing during oogenesis are not well understood. Here, we have examined the expression and localisation of the TATA-binding protein (TBP) and the related protein TBP2 (also called TRF3, TBP-related factor 3) during oogenesis and in early mouse embryos. We show that TBP is expressed in the oocytes at the beginning of folliculogenesis, but it is undetectable during further stages of oocyte development, and becomes abundant again only after fertilisation. In contrast to TBP, we found that TBP2 is highly expressed in growing oocytes during folliculogenesis, declines upon ovulation, and is almost undetectable after fertilisation by the two-cell stage. The mirroring localisation profile of TBP and TBP2 suggests different roles for the two proteins in establishing specialised programs of gene expression during oocyte development and in early mouse embryos. Analysis of mutant mouse ovaries in which oocyte-specific factors have been knocked-out suggests that TBP2 is a potential candidate for regulating transcriptional control of oogenesis. Moreover, our results obtained with oocytes lacking the oocyte-specific nuclear chaperone nucleoplasmin 2 suggest that TBP2 function may be related to non-condensed chromatin conformation.