Characterization of the isoforms of type IIb sodium-dependent phosphate cotransporter (Slc34a2) in yellow catfish, Pelteobagrus fulvidraco, and their vitamin D3-regulated expression under low-phosphate conditions
Characterization of the isoforms of type IIb sodium-dependent phosphate cotransporter (Slc34a2) in yellow catfish, Pelteobagrus fulvidraco, and their vitamin D3-regulated expression under low-phosphate conditions
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黄颡鱼中 IIb 型钠依赖性磷酸盐协同转运蛋白 (Slc34a2) 异构体的表征及其在低磷酸盐条件下维生素 D-3 调节的表达
DOI：
10.1007/s10695-016-0282-7
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发表时间：
2017-02-01
影响因子：
2.9
通讯作者：
Wang, Chunfang
中科院分区：
文献类型：
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作者：
Chen, Pei;Huang, Yanqing;Wang, Chunfang
本研究采用快速扩增cDNA末端的方法，从黄颡鱼（Pelteobagrus fulvidraco）的肠道和肾脏中克隆了slc34a2基因的两个亚型slc34a2a2和slc34a2b。比较了黄颡鱼slc34a2 3种异构体在低磷条件下的结构差异及饲料VD3的调节作用。预测的Slc34a2a2和Slc34a2b蛋白分别与Slc34a2a1匹配65%和53.8%的序列同一性。这三种亚型的跨膜结构域不同。肠道Slc34a2a1和Slc34a2a2蛋白有8个和11个跨膜结构域，而肾脏Slc34a2b蛋白有9个跨膜结构域。组织分布研究表明，slc34a2a2 mRNA主要分布于肠道，slc34a2b mRNA主要分布于肾脏，与slc34a2a1 mRNA分布一致。通过qPCR评估维生素D-3（VD3）水平对低磷酸盐条件下slc34a2亚家族表达的影响，所述低磷酸盐条件通过添加0（VD0）、324（VD1）、1243（VD2）、3621（VD3）、8040（VD4）或22700（VD5）IU VD3/kg饲料诱导。肠slc34a2a2的剂量反应性表达和肠slc34a2a2在VD5中的高表达以及肾slc34a2b在VD3中的峰值表达与体磷含量的积累相一致。这些数据表明，适当水平的饲料VD3上调slc34a2a1，slc34a2a2和slc34a2b的mRNA水平，从而增加磷潴留。因此，本研究通过在低磷饲料中添加适当水平的维生素D3来调节黄颡鱼肠道和肾脏slc34a2基因的表达，从而减少黄颡鱼对磷的排泄，为改善黄颡鱼对磷的利用提供了另一种可能的途径。
In this study, two isoforms slc34a2 genes (type IIb sodium-dependent phosphate cotransporter), slc34a2a2 and slc34a2b, were cloned from intestine and kidney of yellow catfish (Pelteobagrus fulvidraco), with rapid amplification of cDNA ends. The structure differences and the regulation effects of dietary VD3 under low phosphorus were compared among three isoforms of slc34a2 in yellow catfish. The predicted Slc34a2a2 and Slc34a2b proteins match 65 % and 53.8 % sequence identity, with Slc34a2a1, respectively. The membrane-spanning domains were different among these three isoforms. Intestinal Slc34a2a1 and Slc34a2a2 proteins had eight and eleven transmembrane domains, while renal Slc34a2b protein had nine. The tissue distribution study showed that same as slc34a2a1, slc34a2a2 mRNA was mainly distributed in intestine and slc34a2b mRNA in kidney. The effect of vitamin D-3 (VD3) level on slc34a2 subfamily expression under low-phosphate conditions, induced by the addition of 0 (VD0), 324 (VD1), 1243 (VD2), 3621 (VD3), 8040 (VD4), or 22700 (VD5) IU VD3/kg feed, was assessed by qPCR. The dose-responsive expression of intestinal slc34a2a2 and high expression of intestinal slc34a2a2 in VD5 together with peak expression of kidney slc34a2b in VD3 coincided with the accumulation of body phosphate content. These data suggested that appropriate level of dietary VD3 up-regulated slc34a2a1, slc34a2a2, and slc34a2b mRNA levels, which increased phosphate retention. In conclusion, the current study provided another possible approach to improve dietary phosphate utilization by adding appropriate level of VD3 to a low-phosphate diet to regulate intestinal and renal slc34a2 gene expression and thus minimize the excretion of phosphorus in yellow catfish.