Variants of core histones and their roles in cell fate decisions, development and cancer

Histone variants endow chromatin with unique properties and show a specific genomic distribution that is regulated by specific deposition and removal machineries. These variants - in particular, H2A.Z, macroH2A and H3.3 - have important roles in early embryonic development, and they regulate the lineage commitment of stem cells, as well as the converse process of somatic cell reprogramming to pluripotency. Recent progress has also shed light on how mutations, transcriptional deregulation and changes in the deposition machineries of histone variants affect the process of tumorigenesis. These alterations promote or even drive cancer development through mechanisms that involve changes in epigenetic plasticity, genomic stability and senescence, and by activating and sustaining cancer-promoting gene expression programmes.