Aqueous denaturation of wheat embryo ribonucleates

Abstract

1. If wheat embryos are extracted with aqueous phenol, and the aqueous phase is made 2.5 M with respect to NaCl, at 0°C, there is selective precipitation of about 80 % of the total RNA. This “insoluble” fraction of RNA has been designated as NaCl-insoluble RNA. 2. After being subjected to multiple precipitations from aqueous 2.5 M NaCl, at 0°C, and to subsequent solvent dispersals in aqueous ethanol and ether, wheat embryo NaCl-insoluble RNA is virtually pure, free of nuclease contamination and readily susceptible to aqueous denaturation. 3. When subjected to aqueous denaturation, wheat embryo NaCl-insoluble RNA is characterized by trace amounts of several electrophoretic components, in addition to the much larger quantities of the principal 18-S and 26-S rRNA components. The observed heterodispersity is not affected by the inclusion of Macaloid and/or sodium dodecyl sulphate in preparative media, and is not perceptibly altered when viable rather than commercially milled embryos are used as source material for RNA isolation. 4. The most rapidly migrating of the trace electrophoretic components in wheat embryo NaCl-insoluble iRNA (iRMEC component) is only manifest after the NaCl-insoluble RNA is subjected to preliminary aqueous or thermal denaturation. The possible origin of iRMEC and other trace electrophoretic components is a subject of discussion.