Department of Biological Sciences, Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science & Technology School of Life Science & Technology,Wuhan, Hubei Province 430074, China.
Genomics. 2011 Aug;98(2):112-9. doi: 10.1016/j.ygeno.2011.04.010. Epub 2011 May 4.
Na(+)-coupled HCO(3)(-) transporters (NCBTs) of the SLC4 family play critical roles in pH regulation as well as transepithelial HCO(3)(-) transport. We systematically examined, in the mouse reproductive tract tissues, the mRNA expression of five NCBTs as well as the five NBCe1 (Slc4a4) variants NBCe1-A through -E, of which NBCe1-D and NBCe1-E are novel. Cloning of NBCe1-D and NBCe1-E, both lacking a 27-nucleotide cassette I, reveals a novel alternative splicing unit in the mouse Slc4a4 gene. Transcripts of Slc4a4 lacking cassette I are expressed in diverse murine tissues as shown by RT-PCR analysis and in diverse tissues of other vertebrate species as shown by blast against GenBank database. Genomic sequence analysis indicates that cassette I of SLC4A4 is conserved in all NCBT genes except for SLC4A5, which presumably lost cassette I during its evolution. Our present study represents an important step towards understanding the molecular physiology of NBCe1, and presumably other NCBTs.
钠离子-碳酸氢根协同转运蛋白（NCBTs）家族的 SLC4 成员在 pH 调节以及跨上皮碳酸氢根转运中发挥着关键作用。我们系统地检测了小鼠生殖道组织中 5 种 NCBTs 和 5 种 NBCe1（Slc4a4）变体 NBCe1-A 到 -E 的 mRNA 表达，其中 NBCe1-D 和 NBCe1-E 是新发现的。克隆 NBCe1-D 和 NBCe1-E，它们都缺少一个 27 个核苷酸的盒式 I，揭示了小鼠 Slc4a4 基因中一个新的选择性剪接单元。RT-PCR 分析显示，缺乏盒式 I 的 Slc4a4 转录本在多种小鼠组织中表达，而在其他脊椎动物物种的多种组织中进行 Blast 分析显示，这些转录本在 GenBank 数据库中存在。基因组序列分析表明，除了 SLC4A5 之外，所有 NCBT 基因中的盒式 I 都保守，SLC4A5 可能在其进化过程中丢失了盒式 I。本研究代表了理解 NBCe1 以及可能其他 NCBTs 分子生理学的重要一步。
