Non-histone chromatin proteins during various stages of activity of immunocompetent cells

Abstract

Qualitative and quantitative changes of non-histone chromatin proteins of spleen cells during the primary immune response to sheep red blood cells and aggregated human gamma-globulin were described. Synthesis of non-histone chromatin proteins was measured by labelling with 3H-tryptophan during culture of spleen cells in vitro. Chromatin was isolated and labelled proteins were analysed by polyacrylamide gel electrophoresis. During the immune response to both antigens in chromatin of spleen cells three new fractions of non-histone chromatin proteins were synthesized: fractions F1 - M = 12 000 and H - M = 3 000, specific for sheep red blood cells and fractions I1 - M less than 3 000 and B - M = 120 000, specific for human gamma-globulin. The third antigen-non-specific fraction was synthesized at the time when the primary immune reaction was finishing. These new fractions were synthesized only in one of the analysed subpopulations of spleen cells. In thymocytes (non-fully-differentiated lymphoid cells) all these fractions were absent. Changes of non-histone chromatin proteins in thymocytes during the immune response were similar to those found during stimulation to proliferation by phytohemagglutinin in vitro.

Incorporation of various amino acids into non-histone chromatin protein fractions of spleen cells of mice immunized with IgG

“…With sheep red blood cells the labelled chromatin fractions F (MW 12,000), H (MW 3,000) and F' (MW 12,000) were synthesized. After immunization of mice with low doses (200 #g) of pure IgG, together with complete Freund's adj uwant, two chromatir/fractions are synthesized: I (MW below 3,000) and B1 (MW 120,000) that were similar to the fractions observed after immunization with high doses (20 mg) of aggregated human gamma-globulin, as described in the previous paper (3). The time of the appearance of these two fractions in chromatin was also quite similar to that observed after immunization with aggregated human gamma-globulin.…”

“…Because all these fractions were absent in normal non-immunized spleen cells and disappear when antibody synthesis ceases and absent at the same time in thymocytes as the non-differentiated immunological competent cells (3,4), we suggested a regulatory character of these fractions.…”

“…Radioactivity of [3H]-uridine in chromatin preparations and radioactivity of amino acids in gel slices was measured in triton-toluene scintillation fluid (2,3).…”

“…In previous papers (1,2,3) we reported that during the immune response to sheep red blood cells and aggregated human gamma-globulin, new fractions of non-histone chromatin proteins (N H P) are synthesized in spleen cells of mice. Because all these fractions were absent in normal non-immunized spleen cells and disappear when antibody synthesis ceases and absent at the same time in thymocytes as the non-differentiated immunological competent cells (3,4), we suggested a regulatory character of these fractions.…”

Nonhistone chromosomal protein patterns in leucocytes of inbred chicken and their crosses

“…The fact that NHCP's play an important role in gene activation has been generally accepted (A LLFREY , 1974 ;PAUL & G ILMOUR , 1975 ;McGILLIVRAY, 1976 ;C HIU & H NILICA , 1977 ;H ORST et al, 1981), but the group of gene regulating NHCP's has up to now hardly been characterized. The large number of nonhistone proteins found in different tissues and species may be responsible for this lack of knowledge ; in addition to that it may be assumed that few copies of a protein would suffice for gene regulating activities (M C G ILLIVRAY , 1977) (# 4, 6, 8, 11) …”