800.227.0627

Centromere mitotic recombination in mammalian cells

I. Jaco et al
JCB
Centromeres are special structures of eukaryotic chromosomes that hold sister chromatid together and ensure proper chromosome segregation dur-ing cell division. Centromeres consist of repeated se-quences, which have hindered the study of centromere mitotic recombination and its consequences for centro-meric function. We use a chromosome orientation fl uo-rescence in situ hybridization technique to visualize and quantify recombination events at mouse centromeres. We show that centromere mitotic recombination occurs in normal cells to a higher frequency than telomere recombination and to a much higher frequency than chromosome-arm recombination. Furthermore, we show that centromere mitotic recombination is increased in cells lacking the Dnmt3a and Dnmt3b DNA methyltransferases, suggesting that the epigenetic state of centromeric heterochromatin controls recombination events at these regions. Increased centromere recombination in Dnmt3a,3b-deficient cells is accompanied by changes in the length of centromere repeats,suggesting that prevention of illicit centromere recombination is important to maintain centromere integ-rity in the mouse.