[Features of the chromatin structure of erythrocytes depending on the properties of lysine-rich histones]. / Osobennosti struktury khromatina éritrotsitov v zavisimosti ot svoistv lizinbogatykh gistonov.

A comparative analysis of chromatin from erythrocytes of frog, trout and hen has been performed in correlation with properties of the nucleosomal linker histones of H1 family. In the nucleosomes from frog erythrocytes the linker histone is represented by H1(0)-like variant with amino acid sequence highly homologous to that of the hen histone H5, however the arginine content in the proteins differs (3 mol% in the frog erythrocyte H1 and 12 mol% in the hen erythrocyte H5). On the other hand histone H5 from trout being significantly different in the primary structure from the hen histone H5 is at the same time rich in arginine (9 mol%). The nucleosomal repeat length, estimated by using agarose gel electrophoresis is 201, 213 and 213 b.p. in erythrocyte chromatin from frog, trout and hen, correspondingly. Chromatin packing density in fixed nuclei from erythrocytes of frog, trout and hen as determined using cytophotometric measurements is 0.144, 0.444 and 530 pg/mu 3, correspondingly. The data support the previously made suggestion that the increase in arginine content in nucleosomal linker proteins is connected with the increase of chromatin compaction in the nuclei and elongation of the linker in the nucleosome.

[The role of H2B histones from the sea urchin sperm in the formation of supranucleosome structures]. / Uchastie gistonov H2B spermiev morskogo ezha v obrazovanii nadnukleosomnykh struktur.

The structural role of histone H2B from sea urchin sperm (H2Bsp) has been examined in experiments on reconstitution of chromatin from DNA and core histones taken in three variants: (1) four core histones from sea urchin sperm; (2) four core histones from calf thymus; (3) (H3, H4, H2A) from calf thymus and H2Bsp. It is shown that H2Bsp when present in reconstituted chromatin induces its aggregation. Fidelity of the reconstitution of nucleosomes has been tested using DNase I probe, one- and two-dimensional electrophoresis and electron microscopy. The reconstitutes that contain H2Bsp appear under electron microscope mainly as regular closely spaced large granules, about 450 A in diameter, which are very similar to the granules found in "native" sea urchin sperm chromatin. The reconstitutes formed by four core histones from calf thymus appear as randomly arranged particles, about 100 A in diameter. We conclude that histone H2Bsp participates in interactions between nucleosomes and is involved in the formation of the condensed supranucleosomal structure in sea urchin sperm chromatin.

[Processes of reconstruction and association by nucleosomes with various formations of histones]. / Issledovanie protsessov rekonstruktsii i assotsiatsii nukleosom s razlichnym sostavom gistonov.

The experiments on reconstruction of chromatin (without H1) from DNA and histone octamer containing either H2B from sea urchin sperm (H2B-S) or H2B from calf thymus are reported. It has been shown that H2B-S affects the mode of interaction of histones with DNA during the reconstitution of nucleosomal particles on one hand and on the other hand H2B-S plays a major role in the interactions of reconstituted mononucleosomes. These interactions result in supranucleosomal structures.

[Nucleosomal organization of chromatin from sperm of the bivalve mollusk Swiftopecten swifti]. / Nukleosomnaia organizatsiia khromatine spermiev dvustvorchatogo molliuska Swiftopoecten swifti.

Composition of basic chromosomal proteins from sperm of the bivalve mollusc Swiftopecten swifti is specific: (1) somatic histone H1 is replaced for a sperm-specific one containing three subfractions, enriched in Arg; (2) low molecular weight sperm-specific basic protein (S protein) is present in the chromatin additionally to the histones. It is shown that chromatin from the mollusc sperm has typical nucleosomal organization, however the DNA repeat length is markedly increased (225 bp) on account of the linker region of the nucleosome. It is found using two-dimensional electrophoresis that fraction of the mononucleosomes is heterogeneous and represented by four electrophoretic subfractions which differ in protein composition and length of DNA they contain. Subfraction which differ in protein composition and length of DNA they contain. Subfractions of mononucleosomes in the order of increase of electrophoretic mobility contain along with core histones: (1)--all H1 subfractions, protein X, protein S; (2)--subfraction H1"', protein X, protein S; (3)--protein S. The particles containing only core histones correspond to the most rapidly migrating band. The data show that protein S is, like histone H1, possibly bound to the linker DNA. Interdependence between the presence of sperm-specific non-core (-linker?) proteins, the increase in size of linker DNA and compaction of sperm chromatin is suggested.

[Histones of Salmonidae fishes. Comparative study of histones from different species and intraspecies variability of Oncorhynchus nerka H1]. / Sravnenie gistonov raznykh vidov lososevykh ryb i vnutrividovaia izmenchivost gistona H1 Oncorhynchus nerka.

The comparative electrophoretic properties of erythrocyte histones from 7 Salmonidae species were investigated. Using Na-SDS gel electrophoresis, it was shown that all the species studied possess the erythrocyte-specific fraction of histone H5. High resolution gel electrophoresis in acetic acid--urea gels demonstrated differences in the subfractional composition of histone H1 from erythrocytes and liver of O. nerka. The analysis of the sample of 40 individuals from the same population revealed the existence of intraspecies polymorphism in histone H1 subfractional composition.

[Particulate fractionation and properties of basic proteins of sperm chromatin of bivalve molluscs]. / Chastichnoe fraktsionirovanie i nekotorye kharakteristiki osnovnykh belkov khromatina spermiev dvustvorchatykh molliuskov.

A procedure for particulate fractionation of a composite set of sperm chromatin basic proteins in bivalves consisting of histones and protamine-like proteins has been developed. Some sperm proteins in 4 specimens of molluscs were obtained in individual form using chemical methods and preparative electrophoresis. The amino acid composition of these proteins was assayed. The results obtained are discussed in terms of evolution of sperm chromatin basic proteins.

[Preparation and characteristics of antisera to individual histone fractions]. / Metody polucheniia i kharakteristiki antisyvorotok k individual'nym fraktsiiam gistonov.

A method is described of preparation and characterization of antisera to pure individual histone fractions not conjugated with other proteins or haptens. Rabbits were given two injections of the antigen and the whole immunization schedule took only three weeks. The antisera were characterized by immunofluorescent technique using mouse liver sections and smears of rat liver nuclei.