Non-coordinated histone synthesis with DNA replication and close temporal association of ribosomal proteins and rRNA syntheses in germinating Vicia faba embryos.

Syntheses of DNA, RNA and basic proteins during germination of Vicia faba seeds were examined. Incorporation of [3H]thymidine into DNA reached a maximum peak at approximately 34 h after beginning imbibition and the phase of DNA replication was preceded by active RNA synthesis. When Vicia embryos were labeled with [3H]lysine or E13H]arginine, these isotopes were incorporated into ribosomal proteins and histones. The incorporation studies indicated that the synthesis of ribosomal structural proteins is closely linked with rRNA synthesis and histone synthesis occurs during and also before the phase of DNA replication. Polyacrylamide gel electrophoresis of Vica histones indicated that some histones of Vicia embryos differ from corresponding calf thymus histones in their mobilities.