High molecular weight RNA containing histone messenger in the sea urchin Paracentrotus lividus (original) (raw)

Sea m-chin RNA extracted from early and mesenchyme blastula embryos and oocytes and fractionated on denaturing sucrose density gradients, was hybridized with histone DNA recombinants of Psammechi~us miliaris (clone Xh22) and of Paracentrotus lividus (clone pPH70). Histone sequences are found in the 9 S a.nd larger than 9 S regions of the formamide/sucrose density gradients. The melting of the RNA-DNA duplexes obtained by hybridization of polysomal and high molecular weight RNA of embryos of P. Zividu,s at the stage of early blastula, suggests a degree of heterogeneity in the high M, RNA. The high M, RNA contains at least four of the five histone gene sequences covalently linked.