Frequent mutations of human Mad2, but not Bub1, in gastric cancers cause defective mitotic spindle checkpoint

Han Soo Kim, Hwa Park Kyung, Sun A. Kim, Jing Wen, Woo Park Seung, Byungkyu Park, Chang Woo Gham, Jin Hyung Woo, Hoon Noh Sung, Kun Kim Ho, Si Young Song

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Since the underlying mechanism for the high incidence of aneuploidy in gastric cancer has not clarified, we screened 49 gastric cancers and five gastric cancer cell lines for mutations in the mitotic spindle checkpoint genes, Bub1 and Mad2, and we analyzed the functional consequences of these mutations. The presence of mutations in Bub1 and Mad2 coding sequences was primarily detected by RT-PCR-SSCP and subsequently confirmed by automatic sequencing of either the RT-PCR products and/or the PCR products from genomic DNA. Mad2 was mutated in 44.9% of gastric cancer tissues and one gastric cancer cell line, N87, but not Bub1. Of these, three mutational hotspots at codons 156, 165 and 182 were identified. Mutations at codons 165 and 182 led to amino acid substitutions, whereas the mutation at codon 156 was a silent one. Overexpression of mutant Mad2 in HeLa cells led to the appearance of aneuploid cells in the presence of nocodazole, and this indicated that these mutations caused a defect in MAD2 protein. Wild type and mutant MAD2 protein displayed distinct mobility on two-dimensional gel electrophoresis. Novel mutational hotspots in human Mad2 genes were discovered for the gastric cancers and these mutations caused the functional defects in the spindle checkpoint suggesting that these mutations might be involved in the development and progression of gastric cancer.

Original languageEnglish
Pages (from-to)187-201
Number of pages15
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Volume578
Issue number1-2
DOIs
Publication statusPublished - 2005 Oct 15

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Genetics
  • Health, Toxicology and Mutagenesis

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