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The properties of rat liver and thymus non-histone and nuclear sap proteins were compared. The distribution of total, labile-bound and 0.35 M NaCl extractable non-histone proteins from one organ on polyacrylamide-gel electrophoresis in the presence of sodium dodecylsulphate is quite similar. On electrophoresis non-labelled and 32P-labelled non-histone and nuclear sap proteins from one organ differ from one another both qualitatively and quantitatively. We did not find an appreciable difference between non-labelled non-histone proteins isolated from liver and thymus. The distribution of 32P-labelled non-histone proteins from various organs differs quantitatively rather than qualitatively. Non-labelled and 32P-labelled nuclear sap proteins from liver and thymus differ significantly. 'Free' nuclear sap proteins and the proteins of ribonucleoprotein particles from thymus nuclei contain a great quantity of identical polypeptides, whereas other polypeptides are specific to each of these protein fractions. Upon incubation of nuclei with [gamma-32P]ATP the label is incorporated into all the fractions of nuclear protein. The nuclear proteins are phosphorylated at decreasing rates in the order: labile-bound non-histone proteins greater than firmly bound non-histone proteins greater than 'free' nuclear sap proteins = proteins of ribonucleoprotein particles greater than histones. Nuclear sap and non-histone proteins contain protein kinases capable of phosphorylating both these proteins and histones. Histone phosphorylation is sharply inhibited after addition of DNA, the protein kinases of nuclear sap phosphorylating less effectively the histones complexed with DNA than the non-histone proteins. Both non-histone and nuclear sap proteins contain fractions interacting in vitro with DNA. Denatured DNA binds twice as much 32P-labelled nuclear sap proteins and a little more 32P-labelled non-histone proteins than native DNA. Denatured DNA binds non-histone and nuclear sap proteins much more effectively than native DNA. It was shown by the membrane filter technique that the major part of the nuclear sap and non-histone proteins interacting with native DNA binds to it non-specifically. A certain portion of non-histone and nuclear sap proteins interacts specifically with homologous denatured DNA. The possible role of non-histone and nuclear sap proteins in the regulation of transcription is discussed.
S R Umansky, and
R N Zotova, and
Y I Kovalev
November 1973,
Experimental cell research,
S R Umansky, and
R N Zotova, and
Y I Kovalev
January 1983,
Molekuliarnaia biologiia,
S R Umansky, and
R N Zotova, and
Y I Kovalev
January 1976,
Molekuliarnaia biologiia,
S R Umansky, and
R N Zotova, and
Y I Kovalev
March 1972,
FEBS letters,
S R Umansky, and
R N Zotova, and
Y I Kovalev
April 1978,
European journal of biochemistry,
S R Umansky, and
R N Zotova, and
Y I Kovalev
January 1977,
Postepy biochemii,
S R Umansky, and
R N Zotova, and
Y I Kovalev
March 1977,
Experimental cell research,
S R Umansky, and
R N Zotova, and
Y I Kovalev
August 1976,
The Biochemical journal,
S R Umansky, and
R N Zotova, and
Y I Kovalev
May 1976,
Biochemical and biophysical research communications,
S R Umansky, and
R N Zotova, and
Y I Kovalev
September 1972,
The Biochemical journal,
