A comparative study by sucrose gradient electrophoresis of messenger ribonucleoprotein complexes.

The recently developed method of sucrose gradient electrophoresis has been used in the investigation of mRNA containing particles prepared in an undenatured state. The particles containing messenger RNA migrate as a homogeneous fraction with a mobility different from that of ribosomal praticles. Informosomes and polysomal mRNPs have about the same mobility. On the contrary artificial complexes, formed by the reaction of cytoplasmic binding factor with RNA, migrate as a heterogeneous fraction. The particles carrying mRNA are drastically and irreversibly affected by a treatment with EDTA. Sodium deoxycholate removes some proteins but seems also to denature them. After treatment by high salt or Sodium deoxycholate the mRNPs migrate as a homogeneous fraction showing that all particles are equally affected.