ⓘ CENPA

                                     

ⓘ CENPA

Centromeres are the chromosomal domains that specify the mitotic behavior of chromosomes. The CENPA gene encodes a centromere protein which contains a histone H3 related histone fold domain that is required for targeting to the centromere. CENPA is proposed to be a component of a modified nucleosome or nucleosome-like structure in which it replaces 1 or both copies of conventional histone H3 in the H3-H42 tetrameric core of the nucleosome particle. Alternative splicing results in multiple transcript variants encoding distinct isoforms.

In higher eukaryotes, the recruitment of CENP-a nucleosomes to existing centromeres is an epigenetic process that is independent of the primary DNA sequence. In S. pombe, de Novo recruitment of CENP-a at centromeres are believed to be controlled by "centromeric" heterochromatin around the centromere, and through the mechanism of RNA interference. RNC cut form siRNA, it is complex With Chp1 protein, which binds to pericentromeric heterochromatin. It helps to attract other proteins that eventually leads into a protein complex, which forms the cohesin between the two sister chromatids in pericentromeric heterochromatin. This cohesin is considered significant in the replacement of H3 with the centromere in CENP-A. CENP-A is one of the epigenetic changes, which are believed to distinguish centromeric DNA from other DNA. After CENP-A was added, the centromere becomes self-sustaining, and the surrounding mechanism of the heterochromatin / RNAi is no longer necessary.