title: Existence of differences in repressor properties between serine-rich histones (H5, F2c) from immature and mature pigeon erythroid cells.
abstract: The abilities of H1 and H5 histones from immature and mature pigeon erythroid cells and subfractions of H5 histones with different content of alkali-labile phosphorus to restrict RNA synthesis were compared in an in vitro transcription system with bacterial RNA polymerase. It has been found that: a) H1 histones from both sources exhibit similar efficiency. b) H5 histones from immature cells restrict transcription to a lesser extent than the same histone from the mature erythrocyte. c) The subfraction of H5 histone from immature cells with the higher content of alkali-labile phosphorus restrict transcription less than the subfraction with the lower degree of phosphorylation. The results suggest that H5 histone, which first appears in the erythroblasts in a highly phosphorylated form, does not display its potential 'repressor' properties. During erythrocyte maturation H5 histone is dephosphorylated and this causes the massive inactivation of erythrocyte genome.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D010856:Columbidae; D004900:Erythroblasts / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D006657:Histones / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D006657:Histones