Species-specific 5′-genomic structure and multiple transcription start sites in the chicken Pax5 gene
Species-specific 5′-genomic structure and multiple transcription start sites in the chicken Pax5 gene
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DOI：
10.1016/j.gene.2011.01.008
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发表时间：
2011-05-15
期刊：
影响因子：
3.5
通讯作者：
Fujii, Hodaka
中科院分区：
文献类型：
--
作者：
Fujita, Toshitsugu;Fujii, Hodaka
主分化转录因子（MDF）在细胞谱系定型中发挥决定性作用。配对框 5 (Pax5) 是前 B 细胞分化为成熟 B 细胞所必需的 MDF 之一。在这里，我们分析了鸡成熟 B 细胞系 DT40 中鸡 Pax5 (cPax5) 基因的 5' 基因组结构和转录。我们发现cPax5基因有两个第一个外显子：外显子1A包含长AG重复，而外显子1B具有高GC含量。外显子 1A 和 1B 分别具有 1 个和 3 个主要转录起始位点。半定量RT-PCR表明，从外显子1A和1B转录出相当量的mRNA。有趣的是，cPax5 外显子 1A 的转录起始位点是鸡特异性的。此外，外显子1A上游的cPax5启动子与人和小鼠Pax5启动子没有同源性。因此，调节 Pax5 外显子 1A 转录的机制在物种间可能并不保守。此外，我们还确定了 DT40 细胞基因组中外显子 1A、1B 和 2 的物理结构。我们的结果将有助于阐明控制 cPax5 转录和 B 细胞谱系定型的机制，这些机制在不同物种之间保守或不保守。 (C) 2011 Elsevier B.V. 保留所有权利。
Master differentiation transcription factors (MDFs) play decisive roles in cell lineage commitment. Paired box 5 (Pax5) is one of MDFs essential for differentiation of pre-B cells into mature B cells. Here, we analyzed the 5'-genomic structure and transcription of the chicken Pax5 (cPax5) gene in the chicken mature B cell line, DT40. We showed that the cPax5 gene has two first exons: exon 1A contains long AG repeats, while exon 1B has high GC contents. The exons 1A and 1B had one and three major transcription start sites, respectively. Semi-quantitative RT-PCR revealed that comparable amounts of mRNA are transcribed from the exons lA and 1B. Interestingly, the transcription start site of the cPax5 exon 1A was chicken-specific. In addition, the cPax5 promoter upstream of the exon 1A had no homology with the human and mouse Pax5 promoters. Thus, the mechanisms regulating transcription of the Pax5 exon 1A might not be conserved among species. Furthermore, we determined the physical structure of the exons 1A, 1B, and 2 in the genome of DT40 cells. Our results will be useful for elucidating mechanisms that control cPax5 transcription and B cell lineage commitment, which is conserved or not conserved among different species. (C) 2011 Elsevier B.V. All rights reserved.