Point mutagenesis in mouse reveals contrasting pathogenetic effects between MEN2B‐ and Hirschsprung disease‐associated missense mutations of the RET gene
Point mutagenesis in mouse reveals contrasting pathogenetic effects between MEN2B‐ and Hirschsprung disease‐associated missense mutations of the RET gene
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小鼠点突变揭示了 MEN2B 和先天性巨结肠之间 RET 基因错配正义突变之间的对比致病作用
DOI：
10.1111/dgd.12664
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Enomoto Hideki
中科院分区：
文献类型：
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作者：
Nakatani Taichi;Iwasaki Mitsuhiro;Yamamichi Atsuhiro;Yoshioka Yuta;Uesaka Toshihiro;Bitoh Yuko;Maeda Kosaku;Fukumoto Takumi;Takemoto Tatsuya;Enomoto Hideki
theRETgene错义突变已在多发性内分泌瘤（MEN） 2A/B型和巨结肠病（HSCR：先天性肠神经系统缺失，ENS）中被发现。目前的共识认为，MEN2A/B和HSCR分别由激活和失活突变引起。然而，retmissense突变在体内的生物学意义尚未完全阐明。在本研究中，我们通过基因组编辑将一个MEN2B相关的（M918T）和两个HSCR相关的（N394K和Y791F）RETmissense突变（RetM919T, RetN396KandRetY792F）引入到小鼠硒基因的相应区域，并对ret表达组织进行组织学检查，以了解每个突变在体内的发病影响。RetM919T/+小鼠显示MEN2B相关表型，包括C细胞增生和原发性交感神经节异常增大。在retm919t /‐小鼠中观察到类似的交感表型，表明retm918t通过单等位基因表达具有很强的致病作用。相比之下，携带theRetN394K或Y791F突变的小鼠ENS未发现异常。最令人惊讶的是，retn394k或Y791F的单等位基因表达足以正常的ENS发育，这表明这些突变体在体内发挥了很大的生理功能。本研究揭示了MEN2B -和HSCR -相关retmissense突变之间的不同致病作用，并提示一些HSCR -相关retmissense突变本身既不灭活也不致病，需要其他基因突变参与疾病表达。
Missense mutations of theRETgene have been identified in both multiple endocrine neoplasia (MEN) type 2A/B and Hirschsprung disease (HSCR: congenital absence of the enteric nervous system, ENS). Current consensus holds that MEN2A/B and HSCR are caused by activating and inactivatingRETmutations, respectively. However, the biological significance ofRETmissense mutations in vivo has not been fully elucidated. In the present study, we introduced one MEN2B‐associated (M918T) and two HSCR‐associated (N394K and Y791F)RETmissense mutations into the corresponding regions of the mouseRetgene by genome editing (RetM919T, RetN396KandRetY792F) and performed histological examinations ofRet‐expressing tissues to understand the pathogenetic impact of each mutant in vivo.RetM919T/+mice displayed MEN2B‐related phenotypes, including C‐cell hyperplasia and abnormal enlargement of the primary sympathetic ganglia. Similar sympathetic phenotype was observed inRetM919T/‐mice, demonstrating a strong pathogenetic effect of theRetM918T by a single‐allele expression. In contrast, no abnormality was found in the ENS of mice harboring theRetN394K or Y791F mutation. Most surprisingly, single‐allele expression ofRETN394K or Y791F was sufficient for normal ENS development, indicating that theseRETmutants exert largely physiological function in vivo. This study reveals contrasting pathogenetic effects between MEN2B‐ and HSCR‐associatedRETmissense mutations, and suggests that some of HSCR‐associatedRETmissense mutations are by themselves neither inactivating nor pathogenetic and require involvement of other gene mutations for disease expressivity.