Distinct pools of CENP-A and CENP-C support unique phases of centromere assembly in spermatogenesis.

The centromere is the chromosomal site of kinetochore assembly, defined by the histone H3 variant CENP-A. Each cell cycle, the assembly and maintenance of CENP-A is functionally critical for chromosome segregation. In Drosophila male meiosis, CID (fly CENP-A) is assembled in two phases; prophase of meiosis I and post-meiosis II. Here we investigate the dynamics of the assembly components CAL1 and CENP-C in prophase I and determine the requirements for the second assembly phase. In early prophase I, CENP-C functions with CAL1 to maintain the centromere. In late prophase I, CAL1 is undetectable at centromeres and CENP-C no longer functions in centromere maintenance. Instead CENP-C is critical for meiotic kinetochore recruitment and function. This CENP-C pool also functions in CID assembly post-meiosis II, which is independent of CAL1. In addition to different functional pools of CENP-C, distinct pools of CID protein persist in the male germline, and the synthesis of each pool is uncoupled from its cell cycle deposition timing.