 The N-terminal tails of histones can be modified in several ways, including phosphorylation, acetylation, methylation and ubiquitination.Although certain histone modifications at centromeres seem to serve a purpose—for example, contributing to a higher order organization of chromatins in mouse centromeres—conventional and neocentromeres share very few modifications but arguably still maintain the same function of a centromere.Replenishment of CENPA every cycle, which is important for reestablishing centromere identity, is carried out by HJURP (Holliday Junction Recognition Protein), or Scm3 in fungi and CAL1 in "Drosophila".