Lability of RNA from the Large Cytoplasmic Ribosomal Subunit of the Protozoon Crithidia oncopelti

Abstract

Cytoplasmic ribosomal RNA extracted from C. oncopelti and analyzed by gel electrophoresis at 4.degree. C consisted of 2 components, with MW (relative to E. coli rRNA) of 1.30 .times. 106 and 0.83 .times. 106 daltons, present in equimolar amounts. On heating briefly at 51 .degree. C followed by rapid cooling, the 1.30 .times. 106 RNA completely dissociated into 2 components of MW 0.70 .times. 106 and 0.56 .times. 106 (present in equimolar amounts). A 50% dissociation of the molecule occurred at 28.degree. C. That the integrity of the RNA molecule at low temperatures was maintained by its secondary structure was confirmed by electrophoresis under denaturing conditions (98% vol/vol, formamide). To account for these phenomena, latent cleavage of the molecule in vivo was proposed.