Cosedimentation of pea root polysomes with the cytoskeleton

Abstract

When conventional, high ionic strength buffers were used for the isolation of polysomes from pea roots, only about 10% were retained in the detergent-insoluble pellet, and they were not degraded by endogenous RNase. A low ionic strength, cytoskeleton-stabilizing buffer increased retention to 60%, but polysomes were severely degraded. The RNase inhibitors, ribonucleoside-vanadyl complexes, heparin, KCl and ammonium sulphate lessened degradation but caused release, while Tris-HCl at 15-25 mM was able to prevent degradation without causing release. Cosedimentation of polysomes with the cytoskeleton is not an artefact of adsorption or trapping since isolated polysomes labelled through their nascent polypeptides and added to unfractionated tissue were not retained in the cytoskeletal pellet.