Species nonspecific fraction of non-histone chromatin proteins in mice and rats immunized with bacterial lipopolisaccharides

Summary In the chromatin of spleen cells of mice and rats immunized with lipopolisaccharides fromE. coli, a new species and antigen nonspecific fraction of non-histone chromatin proteins is described. The possible role of this fraction in the regulatory process of gene activation during the immune response as expressed by the synthesis of the IgM class of antibodies is discussed.     

Synthesis of non-histone chromatin proteins of mice in spleen cells and myeloma cells RPC 5 and ABPC 22

Summary Non-histone chromatin proteins of myeloma cells RPCM 5, synthesizing 2A and ABPC 22 synthesizing IgM as well as non-histone chromatin proteins of spleen cells from mice bearing these tumours and from control mice were labelled during culture in vitro with ³H-tryptophan, ³H-leucine or ³H-methionine. Electrophoretic patterns of labelled chromatin proteins indicated, that in myeloma cells, producing spontaneously immunoglobulins, any characteristic fraction of non-histone chromatin proteins, described previously in immunoglobulin producing spleen cells, could not be detected, although the profiles of these proteins in myeloma cells, spleen cells from mice bearing these tumours and control spleen cells varied.     

Incorporation of amino acids into protein by cell-free extracts of penicillium chrysogenum

Summary The preparation of ribosomal particles from P. chrysogenum has been described. After correction to 20°C and extrapolation to infinite dilution, they had sedimentation coefficients of approximately 80S, 60 S, and 40 S. The washed ribosomes plus purified supernatant fraction, KCl and sucrose incorporated C¹⁴-l-amino acids into protein. There was no stimulation of incorporation by ATP, GTP, CTP, UTP, or Mg ions. Incorporation was inhibited by streptomycin and chloramphenicol but not by ribonuclease.The amino acid incorporating system from P. chrysogenum did not resemble bacterial and yeast systems in many respects and reasons for this are discussed.     

Characterization of two major non-histone protein fractions from chromatin of sea urchin embryos

• 1.1. Chromatin of sea urchin embryos was chromatographed on a hydroxyapatite column, and the two largest fractions of proteins desorbed with 0.05 M and 0.2 M Na-phosphate, pH 6.8, were comparatively characterized.
• 2.2. The mol. wt ranges of these fractions were about 18,000 and 14,000 daltons, respectively, at both molarities of the phosphate buffer.
• 3.3. Both fractions at each elution molarity were found to be acidic, and to differ somewhat in their respective amino acid compositions. No important differences related to the stage of development could be detected in this respect.
• 4.4. Upon re-electrophoresis both large fractions resolved in one major and three minor bands. The amino acid composition of the major band was different for the blastula and gastrula chromatin.
• 5.5. It is likely that these fractions contain glycoprotein subunits.

     

Incorporation of amino acids into protein of foetal rabbit diaphragm: effect of insulin.

The incorporation of six L-amino acids into the protein fraction of the diaphragm of foetal and neonatal rabbits has been measured. Insulin stimulates the incorporation of lysine from the 29th day and of glycine from the 31st day of gestation onwards. The incorporation of histidine, serine and threonine is only enhanced in the diaphragm of 16-20 hour-old rabbits; no effect of insulin on the incorporation of leucine has been shown for the period under study.     

DNA-binding specificity of a chromatin non-histone protein fraction of HeLa cells.

The DNA-binding site of a previously characterized non-histone chromosomal protein antigen(s) from HeLa cells was investigated for its species specificity. Treatment with large amounts of micrococcal nuclease abolishes immunoactivity, which can then be recovered by the subsequent addition of human or HeLa DNA to reconstitute the immune complex. Neither rat nor calif DNA exhibits this property, but DNA from monkey cells gives considerable activity. The antigen is not, however, detectable in monkey chromatin.