Thiols attached to rat liver non-histone nuclear proteins.

Up to 88% of the total thiol present in isolated rat liver nuclei can be extracted with 8 M urea 50 mM phosphate pH 7.6. There is approx. 5–10% disulphide material present in this extract. When the thiols were labelled with ¹⁴C-N-ethyl maleimide (¹⁴C-NEM) the thiol material co-electrophoresed with the protein material. If a mixed disulphide was formed with ³⁵S-labelled 5-thio-2-nitrobenzoic acid (Ellman's reagent) the thiol compounds could be removed from the protein by isoelectric focusing in polyacrylamide gel. The mixed disulphides obtained could be resolved into at least 10 components on DEAE cellulose. One of the major components had an estimated molecular weight of 3 000 and did not contain peptide material.     

Quantification of nuclear non-histone proteins by Feulgen-Naphthol Yellow S cytophotometry

Summary Owing to the accumulation of nuclear non-histone protein (NHP) (a) in cells entering the cell cycle from the quiescent state and (b) in continuously cycling cells during G₁ phase, a simultaneous determination of DNA and nuclear NHP is of high potential utility in cell kinetic studies. This paper provides guidelines for a Feulgen-Naphthol Yellow S staining technique for this purpose. It discusses details of the preparation and quantification procedures, and reviews the evidence for a quantitative relationship between nuclear Naphthol Yellow S binding and nuclear NHP.     

Extraction and partial characterization of non-histone nuclear proteins of Schistosoma mansoni.

A pool of nuclear proteins from adult worms of Schistosoma mansoni was analyzed for amino acid composition and found to be compatible with high mobility group (HMG) proteins. One of the schistosome HMG proteins was identified as HMG 2 by one-dimensional and two-dimensional PAGE. Stage-specific differences in the HMG-like protein composition were encountered when adult worms were compared to schistosomula, the larval form. Immobilization of the adult male and female nuclear proteins onto nitrocellulose, followed by hybridization against 32P-F-10, a schistosome sex specific gene encoding a major egg shell protein, revealed distinct banding patterns. On the other hand, a synthetic oligonucleotide, derived from the 3' untranslated end of the F-10 gene and possibly containing one regulatory element of the gene, bound mainly to male low MW proteins.     

The acquisition of egg cytoplasmic non-histone proteins by nuclei during nuclear reprogramming

Inseminated eggs and nuclear transplants of Rana pipiens were labeled with [³H]tryptophan. Both the pronuclei of fertilized eggs and the late gastrula endodermal nuclei of transplants concentrated label during the first cell cycle of the egg, and this label was resistant to boiling TCA. These studies demonstrate that nuclear reprogramming is accompanied by the nuclear acquisition of cytoplasmic non-histone proteins from the egg.     

Demonstration of non-histone nuclear proteins in mouse myeloma. Trial comparative study

The non-histone chromosomal proteins from mouse myeloma cell line X 63-Ag 8.653 have been studied using two dimensional polyacrylamide gel electrophoresis. Our results were compared to previous analysis of other myeloma cell lines.     

Hepatoma-associated non-histone proteins are phosphoproteins preferentially localized in nuclear matrix

1. High molecular weight non-histone proteins (NHP) were isolated from Morris hepatoma 7777 by Sephadex G-100, S-200 chromatography. 2. Specific polyclonal antibodies were raised against these NHP in rabbits. These antibodies recognized specific NHP components present in Morris hepatoma 7777 and 8994, but not in normal rat liver. Hepatoma-associated antigens are phosphoproteins. 3. Immunologically specific NHP of Morris hepatoma are intensively concentrated in nuclear matrix fraction.     

The effect of gamma-radiation on the interaction of DNA with nuclear non-histone proteins.

The interaction of nuclear sap proteins and chromatin non-histone proteins with DNA was studied by two methods: membrane filter technique and chromatography of 32P-labelled proteins on DNA-containing columns. Irradiated DNA binds a slightly greater amount of these proteins and much more firmly than the native DNA. The effect is caused by the appearance of the locally denatured sites in irradiated DNA. Irradiation of non-histone proteins disturbs their specific interaction with DNA more easily than the non-specific binding.     

The erythroid cells of anaemic Xenopus laevis. II. Studies on nuclear non-histone proteins.

The mass ratio of nuclear non-histone protein: DNA in the immature circulating erythroid cells of phenylhydrazine-induced anaemic Xenopus is approximately threefold higher than in mature erythrocytes. This is largely due to the presence of increased amounts of low and intermediate molecular weight proteins in the nuclei of the immature cells. There are a few qualitative differences in the components of this class of proteins between the mature and immature cells, the most notable of which is the presence of a protein of molecular weight approximately 115000 in the former which is not detectable in the latter. These changes are discussed in relation to the changing synthetic capacities of cells and to certain generalizations about the function of the nuclear non-histone protein based on studies of other differentiating systems.     

Adenosine 3',5'-monophosphate-dependent protein kinases of myocardial non-histone nuclear proteins.

Myocardial acidic non-histone nuclear proteins (NHPs) contain endogenous protein kinase activity. Phosphocellulose chromatography of purified NHPs identifies nine separate peaks of protein kinases which can phosphorylate both endogenous and exogenous substrates to a variable degree; endogenous NHPs are the best substrates. Cyclic AMP-stimulated protein kinase induced phosphorylation of endogenous and exogenous substrates; the extent of this stimulation varied according to the protein kinase fraction and substrate used. Cyclic AMP also enhanced NHP-induced stimulation of RNA polymerase activity. This enhancement was dependent on protein kinase-induced phosphorylation of NHPs since it was prevented by alkaline phosphatase pretreatment. It is concluded that nuclear protein kinases regulate myocardial RNA synthesis by enhancing phosphorylation of NHPs and that this regulation is under cyclic AMP control.