Transcription factor CDX2 directly regulates the expression of Ctenopharyngodon idellus intestinal PepT1 to mediate the transportation of oligopeptide
Transcription factor CDX2 directly regulates the expression of Ctenopharyngodon idellus intestinal PepT1 to mediate the transportation of oligopeptide
复制标题
转录因子CDX2直接调控草鱼肠道PepT1表达介导寡肽转运
DOI：
10.1016/j.aqrep.2022.101148
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发表时间：
2022-05-09
影响因子：
3.7
通讯作者：
Liu，Zhen
中科院分区：
文献类型：
--
作者：
He，Zhimin;Cai，Yuyang;Liu，Zhen
草鱼（Ctenopharyngodon idellus，C.idellus）是全球最重要的淡水养殖鱼类之一，通过膳食补充通过肠道寡肽转运蛋白PepT1转运的寡肽可以改善其生长性状。然而，C.idellusPepT1 分子调控机制的许多方面仍不清楚。本研究广泛研究了CDX2对C.idellusPepT1的调控机制。首先，通过哺乳动物两种杂交分析和共定位研究了C.idellusCDX2和SP1的相互作用；克隆了PepT1的启动子序列，其活性被CDX2直接上调。在进一步的研究中，在体内和体外检查了CDX2在mRNA和蛋白质水平上的变化对PepT1表达的影响。当CDX2被抑制时，PepT1 mRNA表达显着降低，其表达变化曲线与CDX2几乎一致。为了解CDX2在蛋白水平上对PepT1表达的调控作用，首先对CDX2的稳定性调控机制进行了初步研究。结果表明，CDX2蛋白通过泛素-蛋白酶体途径被降解，并且CDX2蛋白磷酸化水平的增加降低了其周转率并提高了其在细胞中的积累水平。随着 CDX2 蛋白稳定性的增加，PepT1 的表达显着升高，并且 CDX2 和 PepT1 的表达均受到寡肽的刺激。总之，这些观察结果可能为阐明硬骨鱼中CDX2对PepT1的分子调控机制提供新的线索，并为硬骨鱼肠道寡肽的有效运输提供新的认识和策略。
Grass carp (Ctenopharyngodon idellus, C.idellus) is one of the most important globally cultured freshwater fish species, and its growth trait can be improved by dietary supplementation of oligopeptides which is transported through the intestinal oligopeptide transporter PepT1. However, many aspects of the molecular regulation mechanism ofC.idellusPepT1 still remains elusive. In this study, the regulation mechanism ofC.idellusPepT1 by CDX2 was extensively studied. Firstly, the interaction of theC.idellusCDX2 and SP1 was investigated by mammalian two hybrid assays and co-localization; The promoter sequence of PepT1 was cloned and its activity was directly up-regualted by CDX2. In the further study, the effect of CDX2 changes at both mRNA and protein levels on the expression of PepT1 was examined in vivo and in vitro. The mRNA expression of PepT1 was significantly decreased when CDX2 was repressed and its expression change profile was almost consistent with that of CDX2. To understand the regulation of CDX2 on the expression of PepT1 at protein level, the stability regulation mechanism of CDX2 was initially studied. The results showed that CDX2 protein was degraded via the ubiquitin-proteasome pathways, and increasing phosphorylation level of CDX2 protein declined its turnover and elevated its accumulation level in cells. The expression of PepT1 was significantly elevated with increasing CDX2 protein stability, and expressions of both CDX2 and PepT1 were stimulated by the oligopeptide. In conclusion, these observations may shed new light on the molecular regulation mechanism of PepT1 by CDX2 inC.idellusand provide new perceptions and strategies for the efficient transportation of intestinal oligopeptides in teleost fish.