Histones Isoforms

Histone isoforms are expressed only in S-phase of cell cycle and therefore referred as replication-dependent histones. These are found in numerous clusters with multiple histone genes differing in one of few amino acids. These class of histone gene lack a poly(A) tail but have a short highly conserved stem-loop structure in their 3' untranslated region. The association of genomic DNA during replication along with replication-dependent histones is the 'basal state' of chromatin structure.

Types of histone isoforms Histone H1, Histone H2A, Histone H2B, Histone H3, Histone H4