Identification and location of the histone H2A and H3 genes by sequence analysis of sea urchin (S. purpuratus) DNA cloned in E. coli.

A 2000 base pair (bp) DNA fragment can be excised from sea urchin (S. purpuratus) histone gene repeat units with restriction endonuclease Eco R1. This DNA, which has been cloned in a bacterial plasmid, is known to encompass two of the five histone genes. The fragment has a single endonuclease Hind III cleavage site in one of the genes and a Hae III cleavage site in the other gene. We now report the nucleotide sequences of 62 bp adjacent to the Hind III site and 42 bp adjacent to the Hae III cleavage site. The results identify the cloned DNA as histone genes, show that it codes for histone proteins H2A and H3, and locate and orient H2A and H3 genes with respect to restriction endonuclease sites in the repeat unit.