Mutation analysis of hBUB1, human mitotic checkpoint gene in multiple carcinomas

hBUB1 is a human homolog of yeast mitotic check point gene that prays an im portant role in chromosome segregation. Recently mutations of hBUB1 were re ported in colorectal cancer cell lines, indicating that inactivation of thi s gene could be directly involved in aneuploidy in human carcinoma cells. T o obtain information of the magnitude of hBUB1 inactivation in multiple car cinomas, we examined mutations in 59 multiple carcinoma cell lines showing single base alteration, however, there was no mutation of hBUB1 with amino acid change in these carcinomas. There were four silent mutations at codon 93, codon 735, codon 430 and codon 98 in KYSE190, TE8 esophageal carcinoma cells, KATOIII gastric carcinoma cells and 697 B cell leukemia cells, respe ctively. Two candidates of mutation were identified in TE3 esophageal carci noma cells and 697 B cell leukemia cell line at codon 9 and codon 285, resp ectively. This result suggests that the inactivation of hBUB1 may be very r are in human carcinomas, or restricted to certain cell lines of colorectal carcinomas.