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Functional Complementation Assay for 47 MUTYH Variants in a MutY ‐Disrupted Escherichia Coli Strain
Author(s) -
Komine Keigo,
Shimodaira Hideki,
Takao Masashi,
Soeda Hiroshi,
Zhang Xiaofei,
Takahashi Masanobu,
Ishioka Chikashi
Publication year - 2015
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.22794
Subject(s) - mutyh , biology , complementation , genetics , gene , missense mutation , mutagenesis , mutation , mutant , germline mutation
MUTYH‐associated polyposis (MAP) is an adenomatous polyposis transmitted in an autosomal‐recessive pattern, involving biallelic inactivation of the MUTYH gene. Loss of a functional MUTYH protein will result in the accumulation of G:T mismatched DNA caused by oxidative damage. Although p.Y179C and p.G396D are the two most prevalent MUTYH variants, more than 200 missense variants have been detected. It is difficult to determine whether these variants are disease‐causing mutations or single‐nucleotide polymorphisms. To understand the functional consequences of these variants, we generated 47 MUTYH gene variants via site‐directed mutagenesis, expressed the encoded proteins in MutY ‐disrupted Escherichia coli , and assessed their abilities to complement the functional deficiency in the E. coli by monitoring spontaneous mutation rates. Although the majority of variants exhibited intermediate complementation relative to the wild type, some variants severely interfered with this complementation. However, some variants retained functioning similar to the wild type. In silico predictions of functional effects demonstrated a good correlation. Structural prediction of MUTYH based on the MutY protein structure allowed us to interpret effects on the protein stability or catalytic activity. These data will be useful for evaluating the functional consequences of missense MUTYH variants detected in patients with suspected MAP.