CENP-H, a constitutive centromere component, is required for centromere targeting of CENP-C in vertebrate cells

CENP‐H has recently been discovered as a constitutive component of the centromere that co‐localizes with CENP‐A and CENP‐C throughout the cell cycle. The precise function, however, remains poorly understood. We examined the role of CENP‐H in centromere function and assembly by generating a conditional loss‐of‐function mutant in the chicken DT40 cell line. In the absence of CENP‐H, cell cycle arrest at metaphase, consistent with loss of centromere function, was observed. Immunocytochemical analysis of the CENP‐H‐deficient cells demonstrated that CENP‐H is necessary for CENP‐C, but not CENP‐A, localization to the centromere. These findings indicate that centromere assembly in vertebrate cells proceeds in a hierarchical manner in which localization of the centromere‐specific histone CENP‐A is an early event that occurs independently of CENP‐C and CENP‐H.