The Histone H4 Gene of Strongylocentrotus purpuratus: DNA and mRNA Sequences at the 5' End

The histone genes and histone messenger RNAs of the sea urchin are excellent candidates for sequence analysis from the standpoint of understanding both their genetic control during embryogenesis and the evolution of their particular genetic organization. The function of the histone genes is modulated at distinct developmental stages. Just after fertilization of the egg, the histone genes are selectively activated in a dramatic fashion, with over 60% of new polysomal RNA being histone message (Kedes and Gross 1969; Grunstein and Schedl 1976). As the embryo develops, histone (H1, H2A, H2B) protein “variants” are synthesized. These variant proteins show distinct primary structure differences and occur as a result of the activation of variant histone genes (Ruderman and Gross 1974; Cohen et al. 1975; Newrock et al., this volume). Sequence analysis of the histone genes may uncover the nucleotide signals underlying this regulation.