 The yeast homolog of CUL4A, Rtt101, ubiquitinates histone H3 and promotes nucleosome assembly and CRL4A complexes perform similar functions in human cells.CRL4 complexes also affect histone methylation events and chromatin structure through regulation of histone methyltransferases.The histone H4 monomethylase PR-Set7/SET8 is ubiquitinated on chromatin by CRL4(Cdt2) complexes during S phase and following DNA damage in a PCNA-dependent manner.