Cloning of a novel tumor suppressor gene in Wilms' tumor associated with chromosome instability

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Mosaic variegated aneuploidy type 1A (MVA1A) is a rare autosomal recessive chromosome instability syndrome associated with Wilms'tumor. We designed this study to identify the responsible gene of this syndrome.For this purpose, first, we used complementation cloning strategy. The retroviral library derived human mammary gland was divided into 60 small pool libraries that each including 3000 independent clones. All of the small pool libraries were transfected to immortalized MVA1A cells. Transfected cells were exposed with monastrol, one of anaphase inhibitor, for 24 hours ten times every three days. We obtained 16 candidate genes in. the first screening, but each of them didn't show no clear complementation against the MVA1A phenotype.We also underwent detailed studies about the progression of mitosis in MVA1A cells. We found next two new findings ; (1) When MVA1A cells were exposed with spindle.d epolymerizing agents ; the cells transiently arrested in mitosis by spindle checkpoint, and then overrided this checkpoint. (2) The sister centromeres were dissociated before anaphase. These results suggested that the primary defects of MVA1A were existed in centromere-kinetocore function. Then, we underwent mutation analysis of several known centromere-kinetocore genes, such as CENP-A, CENP-C, HP-1β, Ndc8O, Nuf2, AuroraB, Survivin, INCENP, in MVA1A. No responsible mutation have detected until now.