HIGH-MOLECULAR-WEIGHT ARTIFACTS IN RNA EXTRACTED FROM BLASTOCLADIELLA AT ELEVATED TEMPERATURES

(1) The ribosomal RNA of Blastocladiella zoospores extracted with a p-aminosalycilate-triisopropyl naphthalene sulfonate-phenol mixture at low temperature (0-4°) contains two components of 1.32·106 (25 S) and 0.73·106 (18 S) molecular weight. (2) Zoospore RNA extracted with the same solvent mixture at higher temperatures (30-45°) reproducibly contains three additional components with estimated mol. wt. of 1.99·106-2.05·106, 2.6·106-2.7·106, and 3.2·106-3.35·106. (3) The high-molecular-weight components are stable during repeated centrifugation, and electrophoresis in acrylamide gels with 1 mM EDTA and 0.2% sodium lauryl sulfate present. Heating to 80° for 3 min followed by quick cooling converts these high-mol.-wt. components to the free 1.32·106 and 0.73·106 mol. wt. species. (4) The evidence is consistent with the formation of specific, stable, intermolecular aggregates by combinations of the 18-S and 25-S ribosomal RNA species in the presence of the p-aminosalycilate-triisopropyl naphthalene sulfonate-phenol mixture at only moderately elevated temperatures. © 1969.