Direct demonstration of a complementarity between mRNA and double-stranded sequences of pre-mRNA

Double stranded RNA in heterogeneous nuclear RNA from normal and chronic lymphocytic leukemic lymphocytes

Tritium labelled heterogeneous nuclear RNA (HnRNA) from normal and chronic lymphocytic leukemic (CLL) lymphocytes was investigated before and after fractionation into non-poly(A) containing (-HnRNA) and poly(A) containing (+HnRNA) HnRNA with respect to double stranded RNA (dsRNA). Statistically significant higher amounts of rapidly labelled RNA were recovered from CLL lymphocytes when compared to normal cases. Within the CLL cases a significant linear correlation (r = 0.95) was found between white blood cell counts and the amount of dsRNA in total HnRNA. After fractionation into (-) and (+) HnRNAs the ratios of dsRNAs, expressed as the dsRNA in (-) HnRNA divided by the dsRNA in (+) HnRNA, was lower than the corresponding values in normal cases for all the CLL cases except one. The relationship between (+) HnRNA and the total dsRNA level was different when comparing CLL and normal lymphocytes indicating a RNA processing abnormality.

Repetitive sequences and hairpin-like structures in giant RNA of pigeon erythroid cells

In giant molecules (greater than 45 S) of HnRNA from pigeon bone marrow and peripheral blood erythroid cells a correlation is demonstrated between the amounts of hairpin-like structures and the sequences transcribed from the DNA repetitions. The same correlation is observed in the greater than 45 S poly(A)+ and poly(A)- subfractions.

Autodegradation of pre-mRNA containing nuclear ribo-nucleoprotein particles. The effect of autodegradation on the double-stranded RNA sequences and on the protein composition of particles

The quantitative changes of double-stranded RNA components of nuclear ribonucleo-protein particles containing pre-mRNA was investigated in the course of incubation of particles at 37 degrees C. The incubation of purified nuclear particles revealed the fragmentation of long double-stranded RNA sequences into shorter stretches. The presence of nuclear sap in the incubation mixture resulted in degradation of the double-stranded RNAs into acid soluble products. Autodegradation and/or ribonuclease treatment of nuclear RNP particles is accompanied by quantitative changes in the minor protein constituents of informofer.

Isolation of native DNA fragments containing structural genes at the beginning, in the middle or at the end of the coding strand

A method for the isolation of the DNA fragments containing structural genes at the beginning, in the middle and at the end of the coding strand is described. It involves mechanical or enzymatic shearing, exonuclease treatment, hybridization with mRNA and subsequent retention of DNA-mRNA complex on poly(U)-Sepharose. Hybridization of the DNA fragments with mRNA takes place with high specificity and isolated material is enriched in structural genes. Applications of this method for gene isolation are discussed.