Down-regulation of mitotic checkpoint in transformed human embryo lung fibroblasts induced by N-methyl-N'-nitro-N-nitrosoguaridine.
BACKGROUND
Mutations in mitotic checkpoint genes have been detected in several human cancers, which exhibit chromosome instability. We wanted to know whether mutation of hBub1 could occur in transformed human embryo lung fibroblasts (HELF) cells induced by a chemical carcinogen.


METHODS
HELF cells were transformed by N-methyl-N'-nitro-N-nitrosoguaridine (MNNG), and three flasks of transformed HELF cells (named as T1, T2, and T3) were selected as amplifiers, and mutations of hBub1 in these transformed cells were analyzed by PCR-SSCP and sequencing.


RESULTS
It was found that any one of three transformed cell lines exhibited aneuploidy with a low mitotic checkpoint function. Subsequent PCR-SSCP and sequence analysis showed an AGT to CGT or ATT mutation at codon 80 in hBub1 gene in T1 cells with a resultant change in amino acid sequence.


CONCLUSIONS
Our study demonstrated that the mitotic checkpoint genes could be targets of MNNG.
Yi
Zong-chun
ZC
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China. yizongchun@tsinghua.org.cn
Zhang
Min
M
Fu
Juan-lin
JL
Wang
Zhao
Z
Zhou
Zong-can
ZC
D002461:Cell Line, Transformed; D002869:Chromosome Aberrations; D015536:Down-Regulation; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D008168:Lung / Q000166:cytology; D008769:Methylnitronitrosoguanidine / Q000633:toxicity*; D008938:Mitosis / Q000187:drug effects*; D009154:Mutation; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases
D008769:Methylnitronitrosoguanidine; D011494:Protein Kinases; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases