Lectin-binding proteins in nuclear preparations from rat liver and malignant tumors.

Lectin binding [concanavalin A, biotinylated ricinus communis agglutinin, and biotinylated succinylated wheat germ agglutinin (B-SWGA)] was used to detect the glycosylated proteins associated with a residual protein fraction [insoluble in 4% sodium dodecyl sulfate and termed the nuclear residual fraction (NRF)] or with nuclear matrix preparations from normal rat liver, azo dye (3'-MeDAB)-induced rat hepatoma, and Walker 256 transplantable carcinosarcoma. One- and two-dimensional gel electrophoresis were used with lectins, polyclonal antisera, and monoclonal antibody binding to characterize some of the glycoconjugates. Two polypeptide bands with approximate molecular weights of 95,000 and 55,000, shown previously to be present only in the induced tumor cells and the Walker 256 tumor, were reactive with lectins.

Comparison of chicken erythroid cell nuclear isolation methods using morphological, immunochemical and biochemical criteria.

Chicken erythroid nuclei were prepared using four published methods. Our findings indicate that nuclei prepared by nitrogen cavitation are less likely to be contaminated with plasma membrane fragments than those made by procedures involving cell disruption by hypotonic lysis. However, globin gene sequences were much less sensitive to DNase I digestion in nuclei prepared by nitrogen cavitation.

Specificity of non-histone protein antigens in chicken liver nuclei.

1. Chicken liver nuclei were fractionated by disruption with ultrasound and subsequent precipitation with divatent cations. A small, protein-rich fraction (CS), representing less than 5% of the total nuclear DNA reacted strongly with antisera to dehistonized chicken liver chromatin.

In vivo DNA-protein cross-linking by cis- and trans-diamminedichloroplatinum(II).

When Novikoff hepatoma-bearing rats were given injections of a therapeutic dose of cis-diamminedichloroplatinum(II) (cis-DDP) (7 mg/kg), DNA-protein cross-links could be detected by using antisera to dehistonized chromatin, nuclear matrix, or Novikoff hepatoma cytoskeletal preparation. The extent of cross-linking increased in time up to 24 h after the injection, after which time the DNA-protein cross-links were gradually repaired, with no cross-links detectable at 72 h. trans-DDP in equitoxic (40 mg/kg) dose was very efficient in forming DNA-protein cross-links.

DNA-protein crosslinking by heavy metals in Novikoff hepatoma.

Crosslinking of proteins to DNA was studied in live intact Novikoff ascites hepatoma cells exposed in vitro to salts of chromium VI, III, and II, nickel II, cadmium II, and to CoCl2, As2O3, and AlK(SO4)2. DNA-protein complexes were separated by high-speed centrifugation of cells solubilized in buffered 4% sodium dodecyl sulfate and assayed by polyacrylamide gel electrophoresis. Hexavalent chromium compounds formed DNA-protein complexes very efficiently.