Studies on nuclear deprimerones: isolation, fractionation, characterization and control of gene expression.

A procedure was developed for the isolation of low molecular weight peptides (deprimerones) from calf thymus nuclei and other tissues. These peptides are active in controlling transcription and translation in cell-free systems, and stabilize the double stranded structure of DNA. The procedure involves extraction of nuclei with 80% ethanol at pH 9.

Nuclear deprimerones in rat liver and Novikoff hepatoma.

Extraction of total low molecular weight peptides controlling transcription (deprimerones) from rat liver and Novikoff hepatoma nuclei was perfromed with 80% ethanol at pH 9.5. The extracted material was fractionated on a Sephadex G-25 column and active peptidic fractions were collected as Sephadex fraction II of mol.

Poly(A)-mRNA deprimerones in rat liver and Novikoff hepatoma cells.

The poly (A)-mRNA fraction isolated by chloroform deproteinization of liver polysomes and poly(U)-Sepharose chromatography contains a low molecular weights (congruent to 1000) peptidic fraction. The peptides which we suggested to call deprimerones (1) were extracted with 80% ethanol at pH 9.5; after ethanol evaporation, they were purified on Sephadex G-25 column as a fraction of mol.

Inhibition of exogenous mRNA translation in a cell-free system by chromatin peptides from calf thymus.

Low molecular weight chromatin peptides isolated from calf thymus by affinity chromatography on DNA-cellulose inhibit significantly translation of exogenous isolated mRNA in a reticulocyte cell-free system. Translation with endogenous mRNA present in the system is not inhibited by low peptide concentrations. The data obtained combined with the previous findings suggest that chromatin peptides control gene expression at two levels: transcription and translation.

Control of transcription and translation by low molecular weight peptides (deprimerones) from chromatin and poly(A)-messenger RNA. Implication in the mechanism of carcinogenesis.

Poly(A)-mRNA isolated by phenol/chloroform extraction of rat liver polysomes, subtilism digestion, and poly(U)-Sepharose chromatography, contains a low molecular weight (approx. 1000) peptidic fraction. The peptides were extracted from a poly(A)-mRNA fraction by treatment with 80% ethanol; after ethanol evaporation they were purified on a Sephadex G-25 column and high-performance liquid chromatography on muBondapak C18.