[Semi-centennial history of the nuclear matrix at the turn of the 21st century]. / Poluvekovaia istoriia iadernogo matriksa na poroge 21-go veka.

In 1974, Berezney and Coffey described what they called the nuclear matrix (NM), thus ignoring our priority, since we had isolated and characterized virtually the same skeletal structure 25 years before this discovery. The presence of NM in the live cell was doubted, because of unsuccessful attempts to recognize it in vivo. NM comprises the lamina, extracted nucleoli and an intranuclear fibrogranular network. The internal matrix is very labile, its presence and abundance depending on methods of isolation, whereas the isolated NM can be revealed as granules 25-30 nm in diameter. As the state of the interchromatin space changes with varying in vivo conditions, temperature and methods of isolation, doubts cast upon the very existence of NM are to be regarded as hardly valid, and new progress in its study may be expected in the XXI century.

[Proteins of the nuclear matrix and their phosphorylation in normal and tumor cells]. / Belki iadernogo matriksa i ikh fosforilirovanie v normal'nykh i opykholevykh kletkakh.

The protein composition of the nuclear matrix of normal and tumor cells is discussed. A characteristic feature of the latter is the predominance of high molecular weight polypeptides containing mainly glyco- and phosphoproteins. Only few of them are identified. Nuclear matrix preparations from tumors differ by the presence of fibronectin and phosphotyrosine-containing proteins with a molecular mass of nearly 180 and 170 kDa as well as of high turnover of high molecular weight protein group and inhibition of their biosynthesis by chloramphenicol.

[Effect of colostrum polypeptide on structure and lipid peroxidation in liver nuclei of rats late after gamma-irradiation]. / Vliianie molozivnogo polipeptida na strukturu i perekisnoe okislenie lipidov iader pecheni krys v otdalënnye sroki posle gamma-oblucheniia.

Rats were irradiated by 8Gr in a doze power of 2.33 R per second. A portion of animals were injected subcutaneously with a cow colostrum polypeptide (CP) in a doze of 1 mg per g of body weight before the irradiation and daily after the irradiation during 4 days. In irradiated rat liver nuclei injected with CP the lipid peroxide oxidation was restored. At 90th day after the irradiation the production of dienes and dieneketones in liver nuclei oscillated in normal limits. The structure and cytochrome-c-oxidase activity of the nuclei was restored to 60-90th day after the irradiation.

[The immunochemical demonstration of high-molecular proteins in the nuclear matrix of tumor cells]. / Immunokhimicheskoe vyiavlenie nekotorykh vysokomolekuliarnykh belkov v iadernom matrikse opukholevykh kletok.

For characterization of a high molecular-weight protein group prevailing in the tumor nuclear matrix, monoclonal antibodies to MAP-like protein p260 and to fibronectin were used. Immunoperoxidase reaction in Western blots of nuclear matrix electrophoregrams revealed protein p260 both in normal liver and hepatomas 27 and 22a while fibronectin was found in hepatomas, but absent in the normal liver. Immunoelectron microscopy with gold-conjugated antibodies showed p260 to be uniformly spread in the nuclei while fibronectin was localized mostly at the periphery of the tumour nuclei.

[Characteristics of protein metabolism in labyrinthine tissue]. / Osobennosti belkovogo obmena v tkaniakh ushnogo labirinta.

The synthesis of total protein in organic culture of the internal ear was studied in 16-day embryo of CBA mice exposed to altering factors. The experiments showed feasibility of partial recovery for impaired metabolic processes in the labyrinth following phonophoretic introduction of mitochondrial coenzymes and inhibitors of lysosomal activity. Formation of systemic structural trace by modelling of acoustic stress and verification of protein stress agents was tested making it possible to identify an important component in dysadaption mechanism in mature CBA mice labyrinth.

[Effects of gamma irradiation on biosynthesis of nuclear matrix proteins of the liver in pregnant rats and their embryos]. / Vliianie gamma-oblucheniia na biosintez belkov iadernogo matriksa pecheni beremennykh krys i ikh émbrionov.

A study was made of the incorporation of 35S-methionine into nuclear matrix proteins of hepatic cells of pregnant rats and their embryos subjected to single gamma-irradiation (60Co, 1 and 2 Gy, 0.0233 Gy/s) on days 3, 13 and 17 of pregnancy and embryogenesis. On day 21 of pregnancy and embryogenesis a decrease in the rate of incorporation of 35S-methionine into nuclear matrix proteins was shown to be a function of radiation dose and time of pregnancy and embryogenesis on the moment of exposure.

[The effect of gamma irradiation on the structure and enzymatic activity of the nuclear membrane of the liver in pregnant rats and their embryos]. / Vliianie gamma-oblucheniia na strukturu i fermentativnuiu aktivnost' iadernoi obolochki pecheni beremennykh krys i ikh émbrionov.

Morphological and biochemical investigations of pregnant rats and embryo liver cell nuclei after in vivo irradiation in the doses of 1 and 2 Gr revealed their high radiosensitivity at all stages of gestation and embryonal development. At damaging effect of radiation, we managed to observe sharp accumulation of products of lipid peroxide oxidation and suppression of the activities of such enzymes as cytochrome-c-oxidase, NAD.N-cytochrome-c-reductase, ATPase and RNAase in liver nuclei of pregnant rats and embryos. The changes of such a kind are shown to intensify with the increasing of irradiation doses. The most profound inhibition of the activities of these enzymes in liver nuclei of embryos irradiated in utero was observed during the period of organogenesis (the 13th day of the development) and in fetal period of embryogenesis (the 17th day of the development), as well as at the 13th and 17th day of gestation. The morphological data also demonstrate the high level of cell nucleus sensitivity to the action of radiation during gestation and embryogenesis.

[Protein kinase activity of proteins extracted by triton X-100 from isolated rat liver cell nuclei and Zajdela hepatoma]. / Proteinkinaznaia aktivnost' belkov, ékstragiruemykh tritonom X-100 iz izolirovannykh kletochnykh iader pecheni krysy i gepatomy Zaidela.

Proteins extracted with Triton X-100 from rat liver tissue and Zajdela hepatoma nuclei exhibited similar electrophoretic properties of both proteins and phosphoproteins if they were separated by means of electrofocusing. Four protein-kinase activity peaks were detected in each of these preparations. Three protein-kinases from rat liver tissue and Zajdela hepatoma were similar in their electrofocusing point and substrate specificity. However, the fourth protein-kinase, which had pI 6.1-6.3 and was activated by rabbit muscle thermostable proteins, was detected only in the preparation of rat liver tissue, while the enzyme with isoelectric point at pH 4.0 was found only in Zajdela hepatoma preparation. All the protein-kinases studied phosphorylated nuclear matrix proteins at higher rate as compared with histones.

[Proteolytic degradation of nuclear matrix proteins in the rat liver, Zajdela's hepatoma and hepatoma 22A in the presence of ATP]. / Proteoliticheskii raspad belkov iadernogo matriksa pecheni krysy, gepatomy Zaidela i gepatomy 22A v prisutstvii ATF.

An intense proteolytic degradation of both proteins and phosphoproteins has been observed in isolated nuclear matrices from rat liver, Zajdela Hepatoma and Hepatoma 22a, incubated with NP-40, DTT and gamma-[32P] ATP being most intense in Hepatoma 22a. Practically all phosphoproteins of Hepatoma 22a nuclear matrix degraded. This implies either an extremely high proteolytic activity in the preparation or the presence of a specific to phosphoproteins protease absent from rat liver and Zajdela Hepatoma nuclear matrices.

[Skeletal structures of the cell nucleus in the normal state and pathology]. / Skeletnye struktury kletochnogo iadra v norme i pri patologii.

The structure and composition of the nuclear skeleton (nuclear matrix) are considered. The literature data are referred to and the findings of the original author's research on the associations of the nuclear matrix with DNA, its involvement in the control of replication and transcription occurring on the nuclear matrix sites. Special attention is given to the protein composition of the nuclear matrix, and to its changes in tumour growth, virus infection, as well as during mitosis and embryonal development.

[Effect of actinomycin D, cycloheximide, puromycin and mitomycin C on the biosynthesis of heat shock proteins in the nuclear matrix of Chinese hamster fibroblasts]. / Vliianie aktinomitsina D, tsiklogeksimida, puromitsina i mitomitsina C na novoobrazovanie belkov teplovogo shoka iadernogo matriksa fibroblastov kitaiskogo khomiachka.

The thermal shock proteins with molecular mass of 86 kD and pI 5.5 as well as of 70 kD and pI 5.2-5.4 were isolated by means of two-dimensional electrophoresis in polyacrylamide gel from nuclear matrix of chinese hamster fibroblasts after heating of the animals. Incorporation of 35S-methionine into the thermal shock proteins was completely inhibited by actinomycin D (2 micrograms/ml), if the antibiotic was added into the cell incubation medium before heating, while the incorporation of methionine was decreased only slightly when the antibiotic was added after heating of the cells. Thus, biosynthesis of mRNA of the thermal shock proteins of 86 and 70 kD in nuclear matrix was induced by means of an increase in temperature during the incubation of the cells. Biosynthesis of the thermal shock proteins in nuclear matrix was distinctly inhibited by cycloheximide (1 microgram/ml) and was not practically inhibited by puromycin (60 micrograms/ml).

[Heat-shock proteins in the nuclear matrix of Chinese hamster fibroblasts]. / Belki teplovogo shoka iadernogo matriksa fibroblastov kitaiskogo khomiachka.

Heating of Chinese hamster fibroblasts (46 degrees C, 10 min) results in sharp inhibition of protein biosynthesis in the homogenate, nuclei and, in a lesser degree, in the nuclear matrix. The ratio of specific radioactivity of nuclear matrix 35S-proteins to the homogenate radioactivity taken for 100% increases after the heat shock 2,5-fold. Thus, protein biosynthesis in the nuclear matrix is more stable to the damaging action of heat shock than that in the homogenate and nuclei. The nuclear matrix was shown to contain heat shock proteins with Mr of 82-84, 70 and 26 kD, the 70 kD polypeptide being predominant. This polypeptide revealed in 4 hours is intensively accumulated at the 6th hour and remains unchanged by the 17-24th hours after cell heating. The 70 kD heat shock polypeptide can be separated by two-dimensional electrophoresis into two subfractions differing in terms of pI from other proteins revealed within this time interval in the unheated cells.

[Effect of hyperthermia on the polypeptide composition of the nuclear matrix of the rat liver]. / Vliianie gipertermii na polipeptidnyi sostav iadernogo matriksa pecheni krysy.

The increase in rat body temperature by 2-3 degrees as a result of overheating (45 degrees C, 22% humidity) over 90 and 120 min is accompanied by changes in the rate of labeled precursors incorporation into rat liver protein fractions. The incorporation of labeled amino acids into liver nuclear matrix proteins within the first 90 min of overheating is somewhat decreased, whereas 120 min thereafter it exceeds by 30% the corresponding values in control animals kept at room temperature. The polypeptide pattern of the nuclear matrix in hyperthermia is characterized by an increased relative content of polypeptide components around Mr 100, 55, 40 and 30 kDa against a decreased level of several polypeptides as compared to the control.

[Phosphorylation of the nuclear matrix proteins of the liver and of Zajdela's hepatoma in the rat]. / Fosforilirovanie belkov iadernogo matriksa pecheni i gepatomy Zaidelia krysy.

The rate of protein phosphorylation in isolated nuclear matrices from liver and Zajdela's hepatoma is very high, being even slightly higher than in isolated nuclei. This indicates that active protein kinases remain tightly bound to the nuclear matrix, since the areas of phosphorylation are the same. However, during isolation of the nuclear matrix from labeled nuclei in the absence of proteolysis and dephosphorylation inhibitors, most part of the label is eliminated from nuclear matrix proteins. These proteins were phosphorylated in both the tissues, however, in Zajdela's hepatoma, two proteins with a molecular weight of 29-31 kD and four proteins with a molecular weight of 12-19 kD were phosphorylated more intensely than in the liver.