Evidence for possible structural changes of particular H3 and H2B histone genes in different chicken tissues (cells)

The two chicken histone gene families H3 and H2B contain nine and eight members, respectively. To clarify whether the structures of these genes differ in different tissues (and cells), we analyzed DNAs from chicken lung, kidney, oviduct, and sperm. An H3-specific probe (probe 1.3SS) hybridized with a 10 kb EcoRI fragment carrying two H3 genes (H3-II and H3-III) from the lung, kidney, and oviduct with intensities of about one quarter of that of the fragment from the sperm. On the other hand, the intensities of hybridization of the H2B-specific probes (probes H2B-Ia, H2B-IIb, and H2B-III) with a 12 kb EcoRI fragment carrying two H2B genes (H2B-IV and H2B-V) from the oviduct, lung, and sperm were about a quarter of the intensity of hybridization with this fragment from the kidney. These findings, together with those reported previously, suggest that these particular histone genes H3 and H2B possess inherent abilities to form either a tight or loose structure, and that they exist in a loose form in the sperm and kidney but in a tight form in the other tissues tested.