CENP-A is required for accurate chromosome segregation and sustained kinetochore association of BubR1.
CENP-A is an evolutionarily conserved, centromere-specific variant of histone H3 that is thought to play a central role in directing kinetochore assembly and in centromere function. Here, we have analyzed the consequences of disrupting the CENP-A gene in the chicken DT40 cell line. In CENP-A-depleted cells, kinetochore protein assembly is impaired, as indicated by mislocalization of the inner kinetochore proteins CENP-I, CENP-H, and CENP-C as well as the outer components Nuf2/Hec1, Mad2, and CENP-E. However, BubR1 and the inner centromere protein INCENP are efficiently recruited to kinetochores. Following CENP-A depletion, chromosomes are deficient in proper congression on the mitotic spindle and there is a transient delay in prometaphase. CENP-A-depleted cells further proceed through anaphase and cytokinesis with unequal chromosome segregation, suggesting that some kinetochore function remains following substantial depletion of CENP-A. We furthermore demonstrate that CENP-A-depleted cells exhibit a specific defect in maintaining kinetochore localization of the checkpoint protein BubR1 under conditions of checkpoint activation. Our data thus point to a specific role for CENP-A in assembly of kinetochores competent in the maintenance of mitotic checkpoint signaling.
Régnier
Vinciane
V
Department of Biochemistry, Oxford University, South Parks Road, OX1 3QU Oxford, United Kingdom. regnier@ibcg.biotoul.fr
Vagnarelli
Paola
P
Fukagawa
Tatsuo
T
Zerjal
Tatiana
T
Burns
Elizabeth
E
Trouche
Didier
D
Earnshaw
William
W
Brown
William
W
D000818:Animals; D017209:Apoptosis; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D000076247:Centromere Protein A; D002645:Chickens; D002868:Chromosomal Proteins, Non-Histone / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation; D016193:G1 Phase; D018386:Kinetochores / Q000378:metabolism*; D008938:Mitosis; D046912:Multiprotein Complexes / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D049468:Prometaphase; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism
D001324:Autoantigens; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011494:Protein Kinases; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases