This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Takahashi, M. Articles by Ishioka, C. Search for Related Content PubMed Articles by Takahashi, M. Articles by Ishioka, C.

Functional Analysis of Human MLH1 Variants Using Yeast and In vitro Mismatch Repair Assays

¹ Department of Clinical Oncology, Institute of Development, Aging and Cancer, and Tohoku University Hospital, Tohoku University, Sendai, Japan; ² Oncogene Group, Swiss Institute for Experimental Cancer Research, Epalinges, Switzerland; and ³ Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, California

Requests for reprints: Chikashi Ishioka, Department of Clinical Oncology, Institute of Development, Aging and Cancer, and Tohoku University Hospital, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan. Phone: 81-22-717-8547; Fax: 81-22-717-8548; E-mail: chikashi{at}idac.tohoku.ac.jp.

The functional characterization of nonsynonymous single nucleotide polymorphisms in human mismatch repair (MMR) genes has been critical to evaluate their pathogenicity for hereditary nonpolyposis colorectal cancer. We previously established an assay for detecting loss-of-function mutations in the MLH1 gene using a dominant mutator effect of human MLH1 expressed in Saccharomyces cerevisiae. The purpose of this study is to extend the functional analyses of nonsynonymous single nucleotide polymorphisms in the MLH1 gene both in quality and in quantity, and integrate the results to evaluate the variants for pathogenic significance. The 101 MLH1 variants, which covered most of the reported MLH1 nonsynonymous single nucleotide polymorphisms and consisted of one 3-bp deletion, 1 nonsense and 99 missense variants, were examined for the dominant mutator effect by three yeast assays and for the ability of the variant to repair a heteroduplex DNA with mismatch bases by in vitro MMR assay. There was diversity in the dominant mutator effects and the in vitro MMR activities among the variants. The majority of functionally inactive variants were located around the putative ATP-binding pocket of the NH₂-terminal domain or the whole region of the COOH-terminal domain. Integrated functional evaluations contribute to a better prediction of the cancer risk in individuals or families carrying MLH1 variants and provide insights into the function-structure relationships in MLH1. [Cancer Res 2007;67(10):4595–604]

This article has been cited by other articles:

				C. Dherin, E. Gueneau, M. Francin, M. Nunez, S. Miron, S. E. Liberti, L. J. Rasmussen, S. Zinn-Justin, B. Gilquin, J.-B. Charbonnier, et al. Characterization of a Highly Conserved Binding Site of Mlh1 Required for Exonuclease I-Dependent Mismatch Repair Mol. Cell. Biol., February 1, 2009; 29(3): 907 - 918. [Abstract] [Full Text] [PDF]

				G. Klein Toward a genetics of cancer resistance PNAS, January 20, 2009; 106(3): 859 - 863. [Abstract] [Full Text] [PDF]

				Y. Fan, W. Wang, M. Zhu, J. Zhou, J. Peng, L. Xu, Z. Hua, X. Gao, and Y. Wang Analysis of hMLH1 Missense Mutations in East Asian Patients with Suspected Hereditary Nonpolyposis Colorectal Cancer Clin. Cancer Res., December 15, 2007; 13(24): 7515 - 7521. [Abstract] [Full Text] [PDF]