[Identification of Arabidopsis thaliana genes whose expression determines changes in the shoot structure].

A system was created to obtain and select Arabidopsis thaliana genes whose superexpression causes development of a mutant phenotype. Three morphological mutants (two with a markedly retarded growth and one with a fasciated stem) associated with the superexpression of genes At5g10080, At1g33390, and At5g13760 were generated with the use of this system. Localization, structure, and a possible functional organization of these genes were determined.

[New vector system for induction of gene expression in dicotyledonous plants].

A system of two vectors, pEnLox and pCre. was developed. The pEnLox vector is used to induce insertional mutations, while pCre is used to obtain transgenic plants expressing the Cre recombinase gene. The T-DNA enhancer is flanked by the loxP sites in the pEnLox vector. As an Arahidopsis thaliana insertional mutant obtained by transformation with pEnLox is crossed with another transgenic line carrying the cre gene. the enhancer sequence is eliminated. The vector system makes it possible to induce insertional mutations and to determine whether the mutant phenotype is caused by the loss-of-function insertional mutation or by overespression of nearby genes in response to the enhancer contained in the insert.

[Identification of the gene whose mutation leads to the appearance of recessive lethal germlings in Arabidopsis thaliana].

The data are presented on genetic and molecular-genetic analysis of a mutant from the collection of morphological insertion mutants of Arabidopsis thaliana we obtained earlier, which belongs to the phenotypic class of recessive lethal germlings. A nucleotide DNA sequence, 147 bp in size, was identified, which adheres to the left border area of T-DNA insertion. The site of localization of the insertion was determined using computer analysis.

[Identification of the gene whose mutation leads to hypocotyl tropism in Arabidopsis thaliana].

Genetic and molecular analysis of a mutant of Arabidopsis thaliana with bended hypocotyl from a previously obtained collection of insertion mutants is presented. The examined mutation was shown to be recessive and based on a single insertion of pLD3 vector T-region into the A. thaliana genome. Computer-aided analysis of a DNA region adjacent to the left border of the insertion revealed a putative site of T-DNA insertion, the At1g15760 gene from 609-bp chromosome 1 represented by a single exon.

[Identification of the gene whose mutation leads to the morphological changes in the hypocotyl of Arabidopsis thaliana].

The results of genetic and molecular genetic analysis of line 176 of Arabidopsis thaliana with reduced hypocotyls obtained from a previously obtained collection of insertion mutants, are presented. The examined mutation proved to be recessive and based on a single insertion of the T-DNA vector pLD3 into the A. thaliana genome. Computer-aided analysis of the DNA region adjacent to the left border of the insertion revealed a putative site of T-DNA insertion, the 2.5-kb At2g09920 gene located in the long arm of chromosome 2, near the centromere.

[Saving insertional recessive lethal mutants of Arabidopsis thaliana]. / Spasenie insertsionnykh retsessivnykh letal'nykh mutantov Arabidopsis thaliana.

A group of 13 recessive lethal mutants was selected on the basis of the collection of Arabidopsis thaliana transgenic plants with insertions of T-DNA vector plasmid pLD3 or pPCVRN4, which was produced by agrobacterial transformation of germinating seeds. The use of media containing exogenous hormones made it possible to compensate the lethal effect, identify phenotypes, and characterize six lines of recessive lethal germlings using genetic and molecular-genetic methods.

[Creation of a collection of morphological insertional mutants of Arabidopsis thaliana]. / Sozdanie kollektsii morfologicheskikh insertsionnykh mutantov Arabidopsis thaliana.

A collection of transgenic Arabidopsis thaliana plants has been obtained by Agrobacterium-mediated transformation. The genomes of the transgenic plants contain insertions of T-DNA of the vector plasmids pLD3 or pPCVRN4. Genes bearing T-DNA insertions were shown to constitute 12-18% of the total number of A. thaliana genes. Seventy-five lines have been chosen from the collection and subjected to genetic and molecular-genetic analysis. Of these, 5 were dominant mutants, and 70, recessive insertion mutants with various morphological defects. Identification of mutant phenotypes and genetic characterization of the transgenic lines have been performed with the use of nutrient media supplemented with exogenous hormones, which revealed five recessive lethal mutants and one dominant sterile mutant.

[Hormone-dependent insertional Arabidopsis thaliana mutants with decreased viability and fertility]. / Gormon-zavisimye insertsionnye mutanty Arabidopsis thaliana so snizhennoi zhiznesposobnost'iu i fertil'nost'iu.

We present data on the phenotype identification and genetic analysis of offspring in three lines of dominant morphological mutants of Arabidopsis thaliana having drastically reduced fertility (a sterile calluslike mutant, a flower mutant, and a dwarf mutant) and in five lines of recessive morphological mutants (four mutants with lethal seedlings and one pigmentation mutant). The mutants were selected from a collection of transgenic plants that had genomes carrying a T-DNA insertion of plasmid vectors pLD3 and pPCVRN4; the collection was created earlier via agrobacterial transformation of germinating seeds. The results presented here were obtained using compensation of hormonal imbalance in the insertional morphological mutants of A. thaliana by exogenous hormones.

[Identification of mutant gene responsible for cotyledons necrosis in developing seedlings of Arabidopsis thaliana]. / Identifikatsiia gena, mutatsiia v kotorom obuslovlivaet vozniknovenie nekrozov semiadolei pri razvitii prorostkov Arabidopsis thaliana.

Genetic and molecular analyses of an Arabidopsis thaliana mutant with necrotic cotyledons from the collection of insertion mutants obtained earlier were conducted. The mutation under study showed incomplete dominance and represented a single insertion of the T region of pLD3 vector used for transformation of germinating seeds to the plant genome during the creation of the collection. Using TAIL-PCR, a fragment of the mutant DNA adjacent to the left border of the T-DNA insertion was isolated and sequenced. Computer r-aided analysis showed that the insertion was located on the left arm of chromosome 1. The open reading frame containing the insertion has one exon and encodes a protein of 446 amino acids, whose functions are unknown.

[Identification of a gene, included in control of root system development in Arabidopsis thaliana]. / Identifikatsiia gena, vkliuchennogo v kontrol' razvitiia kornevoi sistemy u Arabidopsis thaliana.

Genetic and molecular genetic analysis of a lethal root mutant of Arabidopsis thaliana was carried out. The mutant was obtained from a collection created earlier by means of insertion mutagenesis. The mutation was found to be recessive. It was caused by an insertion of the T region of vector pLD3 used for transformation of germinating seeds when creating the collection of insertion mutants. A 118-bp DNA fragment flanking the left border of the insertion was isolated using the TAIL PCR technique, and its nucleotide sequence was determined. Computer analysis of this DNA region demonstrated that it was located in exon 32 of the YUP8HI2R.44 gene in chromosome 1.

[Insertional mutagenesis of Arabidopsis thaliana: increase of germinating seeds transformation efficiency after sonication]. / Insertsionnyi mutagenez Arabidopsis thaliana: uvelichenie éffektivnosti transformatsii prorastaiushchikh semian v rezul'tate predobrabotki ikh ul'trazvukom.

An efficient procedure of transforming Arabidopsis thaliana germinating seeds was elaborated on the basis of the method of Feldmann and Marks. The procedure involves microdamaging T1 seeds by sonication before culturing with a vector Agrobacterium strain and yields more than 1% T2 transformants. Germinating seeds were transformed with Agrobacterium timefaciens hypervirulent strain A281 carrying plasmid pLD3 derived from pBI121. A collection of 54 A. thaliana T2 transformants was obtained; some of them showed marked morphological alterations. The transgenic nature of plants that acquired resistance to a marker antibiotic was confirmed histochemically and by PCR amplification of a T-DNA region.

[A new open reading frame in the genome of cyanobacteria Synechocystis sp. PCC 6803]. / Novaia otkrytaia ramka schityvaniia v genome tsianobakterii Synechocystis sp. PCC 6803.

A new open reading frame ORF242, coding for a 26.47-kDa polypeptide, was found in a DNA fragment of the cyanobacterium Synechocystis 6803, transforming a photosynthetic mutant to photoautotrophy and having homology with plant chloroplast DNA. In the 5' flanking region of ORF242, consensus sequences characteristic of a functioning gene were found. One copy of ORF242 is present in the Synechocystis 6803 genome. Insertion inactivation of ORF242 does not lead to a decrease in photosynthetic activity in cells of cyanobacteria but may influence the ratio between active complexes of photosystems I and II.

[A vector for constructing transgenic dicotyledonous plants registering recombination in direct DNA repeats]. / Vektor dlia sozdaniia transgennykh dvudol'nykh rastenii registriruiushchikh rekombinatsiiu po priamym povtoram DNK.

A new pLT-5 vector that can be used for transforming dicotyledonous plants was constructed. Its T-region contains direct repeats of the beta-glucuronidase gene fragment. These repeats are located in such a way that their recombination results in the recovery of gene structure and, therefore, of the gene's ability to be expressed in plant cells.

[Cloning of the recA gene of the propionic acid bacterium Propionibacterium shermanii in Escherichia coli cells]. / Klonirovanie recA-gena propionovokislykh bakterii Propionibacterium shermanii v kletkakh Escherichia coli.

Propionibacterium are producers of vitamin B-12 and organic acids and are of importance in national economy. Genetics of this organism was studied insufficiently. We constructed the genomic library of Propionibacterium shermanii in cells of Escherichia coli using the plasmid vector pVZ361 and identified recA gene. The vector gives a chance for direct selection of Str-resistant clones containing an insert in BamHI site. The recombinant plasmid carrying the recA gene of P. shermanii was isolated from the genomic library using complementation in E. coli. Strains E. coli C600 and HB101 were transformed by hybrid plasmids, and UV-light-resistant clones were identified. The clones were purified and subjected to treatment with 4-NQO and MMS. Diagrams reflecting survival dependence of the bacteria carrying recombinant plasmids and lacking them on the mutagen concentration and UV-light dose clearly confirmed functioning of P. shermanii recA gene in E. coli cells. The insert with recA gene underwent restriction analysis. The 1.7 kb fragment with recA gene was then transferred to pBI101 plasmid and the resultant recombinant plasmid was used in the SOS test. The mutagens (MMS, 4-NHQ) and UV-light induced the SOS response in E. coli HB101 (recA) carrying the recombinant plasmid.

[Cloning of alpha-hemolysin gene from Staphylococcus aureus strain 015]. / Klonirovanie gena alpha-gemolizina shtamma Staphylococcus aureus 015.

The genomic library of Staphylococcus aureus O15 has been constructed on the EMBL-3 vector. The synthetic oligonucleotide probes to N- and C-end regions of alpha-hemolysin permitted identification of the recombinant bacteriophage clone RS-1 containing a gene for this protein. The restriction map of the cloned fragment has been constructed for restriction endonucleases SalGI, EcoRV, PstI, PvuII. Expression of the alpha-hemolysin gene in phagolysate of the recombinant clone RS-1 (1000 units per ml) has been demonstrated.

[Cytokinins do not noticeably change the methylation of adenine residues of DNA in cultured Escherichia coli B]. / Tsitokininy zametno ne izmeniaiut metilirovanie adeninovykh ostatkov DNK v kul'ture kletok Escherichia coli B.

6-Benzylaminopurine (6-BAP) (1 mg/ml) does not influence the growth of E. coli B cell cultures or the number of [8-14C] labeled N6-methyladenine (m6A) residues in the total DNA [(100.m6A/(A x m6A) = 1.7]. The growth of bacterial cells in the presence of adenine or cytokinins (6-BAP, kinetin, zeatin) (1 mg/ml) was unaccompanied by significant changes in the intracellular content of plasmid pBR 322. The mode of restriction by endonuclease Cfu I hydrolyzing the Gm6ATC site of plasmids pBR 322 from E. coli B cells grown in the presence of adenine or one of the above-mentioned cytokinins is identical. These plasmids also have identical restriction products Mbo I or Sau 3AI. Thus, the cytokinins under study do not markedly affect the methylation of adenine residues in total DNA of E. coli B cell cultures and the GATC sequence in plasmids pBR 322 isolated from these cells.

[Loss of CpG dinucleotides from DNA. VI. Methylation of mitochondrial and chloroplast genes]. / Poteria dinukleotidov CpG iz DNK. VI. Metilirovanie genov mitokhondrii i khloroplastov.

From nucleotide sequences of mitochondrial and chloroplast genes the probable frequency of the CpG----TpG + CpA substitutions was determined. These substitutions may indicate the level of prior DNA methylation. It was found that the level of this methylation is significantly lower in mitochondrial DNA (mtDNA) and chloroplast DNA (chDNA) than in nuclear DNA (nDNA) of the same species. The species (taxon) specificity of mtDNA and chDNA methylation was revealed. A correlation was found between the level of CpG methylation in nDNA, and mtDNA and chDNA in different organisms. It is shown that cytosine residues in CpG were not subjected to significant methylation in the fungi and invertebrate mtDNA and also in the algae chDNA. In contrast, the vertebrate mtDNA bears the impress of CpG-supression, which is confirmed by direct data on methylation of these DNA. Here the first data on the possible enzymatic methylation of the plant mtDNA and chDNA were obtained. It was shown that the degree of CpG-suppression in the 5S rRNA nuclear genes of lower and higher plants is significantly higher in the chloroplast genes of 4,5S and 5S rRNA. From data on pea chDNA hydrolysis with MspI and HpaII it was established that in CCGG sequences this DNA is not methylated. The role of DNA methylation in increasing the mutation rate and in accelerating the evolutionary rates of vertebrate mtDNA is discussed.