[Intragenomic polymorphism of the primary structure of 5S rRNA gene variants of the loach (Misgurnus fossilis L.). Determination of the transcriptional activity]. / Vnutrigenomnyi polimorfizm pervichnoi struktury variantov genov 5S rRNK v'iuna (Misgurnus fossilis L.). Opredelenie transkriptsionnoi aktivnosti.

The primary structure of 12 cloned repeats of loach oocyte 5S rRNA genes was determined. The heterogeneity of nucleotide sequences was revealed in the coding regions and spacer of the genes. The results of the study on in vivo transcriptional activity of the cloned 5S rRNA gene variants are consistent with the localisation of site specific base substitutions in the coding part affecting the transcription. We have compared the nucleotide sequences of loach 5S rRNA gene variants and of Xenopus laevis, X. borealis and Bombyx mori 5S genes which can be actively transcribed in X. laevis oocyte nuclei. As a result we could propose a consensus nucleotide sequence in the internal control region (from 45-th up to 100-th nucleotide) of the eukaryotic 5S rRNA gene. This sequence comprises a RNA-polymerase III promotor and stretches interacting with transcriptional factors. We have considered the base substitutions in the nucleotide sequences of 5S gene variants exerted on the experimental model of loach 5S rRNA secondary structure. All base substitutions in actively transcribed genes do not influence the general double-stranded structures of the transcripts. However in 5S RNA transcripts from genes with low transcriptional activity base substitutions affecting the box c RNA-polymerase III promoter destroy hairpin II interacting with ribosomal proteins. We have concluded that two factors can restrict the divergency of 5S rRNA genes: (1) conservation of the nucleotide sequence in the gene internal control region, and (2) conservation of the general double stranded structures in 5S rRNA transcripts.

[Regulation of transcription of immunoglobulin kappa genes in Xenopus laevis oocytes]. / Reguliatsiia transkriptsii kappa-genov immunoglobulinov v ootsitakh shportsevoi liagushki.

Recombinant plasmids containing the immunoglobulin kappa gene with deletions in the 5' and 3' regions of the gene having different position and orientation of the enhancer element were constructed. The plasmids were incubated with cell-free extracts prepared from lymphoid and non-lymphoid cells, and then injected into the nuclei of Xenopus laevis oocytes. Tissue-specific transcription of the V kappa gene was shown to be under control of factor(s) existing in lymphoid cells. The data reported in this paper allow to suggest that, along with the positive transcription control regions located in the 5' region of the gene and in the J-C intron, there is also a negative control region situated in the J-C intron as well. Possible role of the tissue-specific factors from lymphoid cells is to abolish the negative control.

[Properties of the RNA-component informosome from amphibian oocytes]. / Nekotorye svoistva RNK-komponenta informosom ootsitov amfibii.

RNA synthesis in in vivo ovulated oocytes of Rana temporaria frog was studied. It was shown that RNA synthesised during oocyte maturation is non-mitochondrial and is localized mostly in the ribonucleoprotein fraction; the bulk of the RNA is present in informosomes. The RNA extracted from informosomes shows a heterogeneous sedimentative distribution with predominant components of 19S and 26-27S. This RNA does not adsorb on oligo(dT)-cellulose columns.

[Informosome formation in maturing amphibian oocytes]. / Obrazovanie informosom v sozrevaiushchikh ootsitakh amfibii.

[14C]Uridine and/or RNA-binding [3H]protein preparations were microinjected into the oocytes of Rana temporaria frog. It was shown that both labelled compounds are incorporated into RNP particles with the buoyant density in CsCl characteristic of informosomes and with a homogeneous sedimentation distribution in sucrose gradients. Injection of actinomycin D into recipient oocyte leads to inhibition of synthesis of the informosome RNA component as well as to the incorporation of RNA-binding [3H] proteins into free informosomes. The results obtained provide experimental proofs for the assumption that the RNA-binding proteins under study form complexes predominantly with newly synthesized RNA.

[Repair of mitochondrial DNA after x-ray irradiation of teleost fish loach Misgurnus fossillis eggs]. / Reparatsiia mitokhondrial'noi DNK posle rentgenovskogo oblucheniia iaitsekletok v'iuna Misgurnus fossilis.

X-ray irradiation of loach Misgurnus fossilis mature eggs induces breaks in mtDNA molecules with efficiency about 100 ev per break. The yield of damaged molecules of mtDNA reduces after fertilization or activation of irradiated eggs and subsequent incubation. Two-fold reduction in the relative amount of broken DNA molecules in mitochondria is observed after an 6-7 hour incubation. X-ray irradiation largely accelerates mtDNA synthesis in eggs. Activation of mtDNA synthesis is observed in whole irradiated eggs and in mitochondria isolated from them as well. Appearance of nascent DNA in the broken mtDNA molecules indicates the repair nature of mtDNA synthesis induced by X-irradiation.

[RNA-binding proteins of Rana temporaria oocytes: incorporation into informosomes of oocytes in vivo]. / RNK-sviazyvaiushchie belki ootsitov liagushki Rana temproaria: vkliuchenie v sostav informosom ootsitov in vivo]

The participation of RNA-binding protein in the formation of informosomes in vivo was studied using an intracellular microinjection technique. The RNA-binding protein of the frog Rana temporaria oocytes was isolated by affinity chromatography and was labelled in vitro without any loss of its activity. It was shown that during cultivation of the oocytes the specific incorporation of the injected RNA -- binding [3H]-protein into the ribonucleoprotein particles occurred. These particles were further described as informosomes, characteristic ribonucleoprotein particles of animal cells.

[Induction of oocyte maturation at stages of incomplete vitellogenesis in toads and the starred sturgeon]. / Induktsiia sozrevaniia ootsitov shportsevoi liagushki i sevriugi na stadiiakh nezavershennogo vitellogeneza.

The intracellular injection of cytoplasm from the maturing oocytes of X. laevis and A. stellatus in oocytes of the same species which did not complete the vitellogenesis and are not able to mature under the effect of progesterone resulted in the disintegration of the germinal vesicle membrane in the oocytes of all sizes under study. In X. laevis the ability to mature under the effect of progesterone appears in the oocytes with the diameter over 1.1 mm. Cycloheximide inhibits the germinal vesicle membrane disintegration in the X. laevis oocytes, but not in those of A. stellatus. Cycloheximide inhibits the pseudogastrulation which was observed in the X. laevis oocytes with the diameter from 0.8 to 1.4 mm.

[Study of the cytostatic action of the cytoplasm of oocytes and mature ova of the common frog and sturgeon (Acipenser stellatus)]. / Izuchenie istitostaticheskogo deistviia tsitoplazmy ootsitov i zrelykh iaits travianoi liagushki i sevriugi.

The presence of the cytostatic factor found by Masui and Markert (1971) in the cytoplasm of oocytes and eggs of Rana pipiens was verified in the cytoplasm and mature inactivated eggs of the common frog Rana temporaria and sevryuga Acipenser stellatus. The cytoplasm was injected to the embryos of the same species at different phases of the first cleavage division in the animal region of one of the two blastomeres. The injection of cytoplasm did not cause the arrest of cleavage divisions. Many embryos proceeded to gastrulation. The cytoplasm of maturing oocyte and mature egg in the common frog and sevryuga, unlike in R. pipiens, has no cytostatic effect.

[Effect of cycloheximide on the disintegration of the germinal vesicle membrane and on changes in the cortical layer in oocytes of the clawed toad and the starred sturgeon during maturation on exposure to active cytoplasm]. / Vliianie tsiklogeksimida na dezintegratsiiu obolochki zarodyshevogo puzyr'ka i izmeneniia kortikal'nogo sloia v ootsitakh shportsevoi liagushki i sevriugi pri sozrevanii ikh pod deistviem aktivnoi tsitoplazym.

There was studied the effect of cycloheximide on the changes in the X. laevis and A. stellatus oocytes maturing under the influence of active cytoplasm, taken from the maturing oocytes, and, in the control series, under the influence of progesterone. The suppression of protein synthesis in the X. laevis oocytes by means of cycloheximide by 90--95% did not prevent the amplification of the factor of disintegration of the germinal vesicle membrane after 4 and 5 transfers of the active cytoplasm through the cycloheximide-treated oocytes; no pseudogastrulation was observed in such oocytes. Under the similar suppression of protein synthesis in the A. stellatus oocytes, the germinal vesicle did not break down already after the first injection of active cytoplasm; such oocytes acquried, however, the ability of cortical reaction. The cycloheximide-treated oocytes of both the species did not mature under the effect of progesterone. The fully grown A. stellatus oocytes matured after the injection of active cytoplasm from the mature X. laevis oocytes.