title: Histones in the first cleavage cycle of fertilised sea urchin eggs.
abstract: Nuclei were isolated from Echinus eggs through the first cleavage cycle by modification of existing techniques. When these nuclei were extracted with 2 M NaCl and the supernatant diluted to 0.15 M, large amounts of non-histone proteins remained in solution. The precipitated nucleoprotein contained expected amounts of DNA and a protein analogous to mammalian histone H1. Extrachromosomal histone H1 was eliminated by the modified isolation procedure. Amounts of nuclear proteins soluble in 0.15 M NaCl reached a peak in G2. Histones and non-histone proteins were phosphorylated postfertilization, in early prophase and in telophase.
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D005260:Female; D006657:Histones / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D012617:Sea Urchins; D015053:Zygote / Q000378:metabolism*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D010710:Phosphates