Isolation of cDNA clones encoding human histone macroH2A1 subtypes.

cDNA clones encoding two different subtypes of histone macroH2A1, macroH2A1.1 and macroH2A1.2, have been isolated from human liver tissue. The open reading frames in the isolated clones predicted proteins comprising 368 and 371 amino acids respectively. Estimated molecular masses of the two proteins were 39.0 kDa and 39.4 kDa. Human histone macroH2A1.1 and macroH2A1.2 showed about 98% identity with their counterparts isolated from rat. The features of the nucleotide sequences of the two macroH2A1 subtypes in human were the same as in the rat system. Northern blot analysis showed that the macroH2A1.1 and macroH2A1.2 subtypes were expressed as mRNA species with a size of 1.5 and 4.4 kb, respectively. They were expressed in all human tissues examined.