HIGH MOLECULAR WEIGHT RNA CONTAINING HISTONE MESSENGER IN THE SEA-URCHIN PARACENTROTUS-LIVIDUS

Sea urchin RNA extracted from early and mesenchyme blastula embryos and oocytes and fractionated on denaturing sucrose density gradients, was hybridized with histone DNA recombinants of Psammechinus miliaris (alone .lambda.h22) and of P. lividus (clone pPH70). Histone sequences are found in the 9S and larger than 9S regions of the formamide/sucrose density gradients. The melting of the RNA-DNA duplexes obtained by hybridization of polysomal and high MW RNA of embryos of P. lividus at the stage of early blastula, suggests a degree of heterogeneity in the high MW RNA. The high MW RNA contains at least 4 of the 5 histone gene sequences covalently linked.