Variant histone proteins allow the induction of specific processes, including DNA repair.
The histone protein H2X replaces H2A to recruit factors involved in DNA repair. This is essential, ensuring the genetic information in the cell is correct. By using a variant histone, the structural change is more easily detected by the DNA repair factors, allowing the damaged section to be repaired.
Replacing H3 with H3.3 allows the replication of chromatin in non-dividing cells. H3.3 maintains genome integrity, with mutation linked to the development of cancers.
The variant histone CENP-A is found at centromeres, allowing both the binding of two daughter chromatin together and the attachment of kinetochore proteins for segregation by mitotic spindle fibres. This enables mitosis and meiosis to occur, which are essential processes for cell division, as well as independent segregation, creating genetic variation between individuals.