all genes in the histone cluster are transcribed at high levels during S-phase, individual histone H2B genes are also expressed at other times during the cell cycle. They are dually regulated by the cluster promoter sequences and their specific promoter sequences. See also Histone code Nucleosome Chromatin Other histone proteins: Histone H1 Histone H2A Histone H3 Histone H4 References Proteins DNA-binding proteins