BubR1- and Polo-coated DNA tethers facilitate poleward segregation of acentric chromatids.
The mechanisms that safeguard cells against chromosomal instability (CIN) are of great interest, as CIN contributes to tumorigenesis. To gain insight into these mechanisms, we studied the behavior of cells entering mitosis with damaged chromosomes. We used the endonuclease I-CreI to generate acentric chromosomes in Drosophila larvae. While I-CreI expression produces acentric chromosomes in the majority of neuronal stem cells, remarkably, it has no effect on adult survival. Our live studies reveal that acentric chromatids segregate efficiently to opposite poles. The acentric chromatid poleward movement is mediated through DNA tethers decorated with BubR1, Polo, INCENP, and Aurora-B. Reduced BubR1 or Polo function results in abnormal segregation of acentric chromatids, a decrease in acentric chromosome tethering, and a great reduction in adult survival. We propose that BubR1 and Polo facilitate the accurate segregation of acentric chromatids by maintaining the integrity of the tethers that connect acentric chromosomes to their centric partners.
Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA. royou@biology.ucsc.edu
Anne
A
Royou
Mary E
ME
Gagou
Roger
R
Karess
William
W
Sullivan
D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002503:Centromere / Q000378:metabolism*; D020090:Chromosome Segregation; D002875:Chromosomes / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D008938:Mitosis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D014960:X Chromosome / Q000378:metabolism
C506005:BubR1 protein, Drosophila; D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; C072004:polo protein, Drosophila; D017346:Protein Serine-Threonine Kinases