Slc26a3/Dra and Slc26a6 in Murine Ameloblasts
Slc26a3/Dra and Slc26a6 in Murine Ameloblasts
复制标题
DOI：
10.1177/0022034515606873
复制
发表时间：
2015-12-01
影响因子：
7.6
通讯作者：
Bronckers, A. L. J. J.
中科院分区：
文献类型：
--
作者：
Jalali, R.;Zandieh-Doulabi, B.;Bronckers, A. L. J. J.
在珐琅质发育过程中形成的磷灰石晶体会产生质子。为了维持矿物的积累，成熟的成釉细胞需要缓冲这些质子。成熟成釉细胞中存在胞质碳酸酐酶、基底外侧Na+碳酸氢盐共转运体Nbce I和基底外侧阴离子交换剂Ae2a，b，这表明这些细胞将碳酸氢盐分泌到形成的珐琅质中，但其机制尚不清楚。溶质载体（Sic）家族26A编码不同的阴离子交换剂，可以交换Cl-/HCO3-，包括Slc26a3/Dra、Slc26a6/Pat- I和Slc26a4/pendrin。先前，我们发现pendrin在成釉细胞中表达，但对牙釉质的形成并不重要。在本研究中，我们验证了成熟成釉细胞表达Dra和Slc26a6以向牙釉质空间分泌碳酸氢盐以换取cr的假设。实时聚合酶链反应检测到小鼠门牙牙釉质器官中Dra和S1c26a6的mRNA转录本，Western blotting证实了它们转化为蛋白质的可能性。这两种异构体在成釉细胞中都有免疫定位，主要是在成熟阶段。通过显微计算机断层扫描测量，Dra或Slc26a6零突变的小鼠具有正常的牙齿或骨骼表型，而矿物质密度没有变化。在slc2606缺失小鼠的牙釉质器官中，Dra和pendrin蛋白水平分别升高52%和55%。Ae2a、b-和cftr缺失小鼠牙釉质器官中Slc26a6蛋白的含量没有变化，而dra缺失小鼠的Slc26a6蛋白含量减少了36%。我们的数据显示，成釉细胞表达Dra、pendrin或Slc26a6，但它们中的每一种对牙釉质的形成都不是至关重要的。这些数据表明，在成釉细胞中，Slc26a异构体可以在功能上相互补偿。
Formation of apatite crystals during enamel development generates protons. To sustain mineral accretion, maturation ameloblasts need to buffer these protons. The presence of cytosolic carbonic anhydrases, the basolateral Na+ bicarbonate cotransporter Nbce I, and the basolateral anion exchanger Ae2a,b in maturation ameloblasts suggests that these cells secrete bicarbonates into the forming enamel, but it is unknown by which mechanism. Solute carrier (Sic) family 26A encodes different anion exchangers that exchange Cl-/HCO3- including Slc26a3/Dra, Slc26a6/Pat- I, and Slc26a4/pendrin. Previously, we showed that pendrin is expressed in ameloblasts but is not critical for enamel formation. In this study, we tested the hypothesis that maturation ameloblasts express Dra and Slc26a6 to secrete bicarbonate into the enamel space in exchange for cr. Real-time polymerase chain reaction detected mRNA transcripts for Dra and S1c26a6 in mouse incisor enamel organs, and Western blotting confirmed their translation into protein. Both isoforms were immunolocalized in ameloblasts, principally at maturation stage. Mice with null mutation of either Dra or Slc26a6 had a normal dental or skeletal phenotype without changes in mineral density, as measured by micro computed tomography. In enamel organs of Slc2606-null mice, Dra and pendrin protein levels were both elevated by 52% and 55%, respectively. The amount of Slc26a6 protein was unchanged in enamel organs of Ae2a,b- and Cftr-null mice but reduced in Dra-null mice by 36%. Our data show that ameloblasts express Dra, pendrin, or Slc26a6 but each of these separately is not critical for formation of dental enamel. The data suggest that in ameloblasts, Slc26a isoforms can functionally compensate for one another.