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The tobacco plant genes NtEXPA1 and NtEXPA4 encode the α-expansin proteins involved in the regulation of cell growth and extension. We examined the levels of expression of these genes in various plant organs and under the effect of exogenous phytohormones. The highest levels of NtEXPA1 expression were registered in the terminal bud and in the young growing leaves and flowers. NtEXPA1 expression ceased once the leaves stopped growing. The NtEXPA4 gene showed a similar expression profile, except for higher levels of mRNA in the leaves. In young leaves located near the terminal bud, high levels of NtEXPA1 and NtEXPA4 are induced by auxins. In the lower leaves, expansin expression is differentially regulated by brassinosteroids, which inhibit NtEXPA1 and upregulate NtEXPA4. We further showed that expression of the transgenic ARGOS-LIKE results in upregulation of NtEXPA1 and a reduction in the NtEXPA4 mRNA. In turn, overexpression of NtEXPA1 resulted in an increased size of the leaves and stems because of the larger size of the individual cells.

Transgenic tobacco plants expressing the fragments of the ARGOS and NtEXPA4 genes in antisense orientation have been created. Eleven lines of transgenic plants were investigated and five of them were characterized by a decrease in the sizes of the leaves and flowers as compared to control. Stalk sizes decreased when only the NtEXPA4 gene fragment was used. The organ size of the experimental plants decreased because of a reduction in the level of both cell division and cell expansion. Two lines of transgenic tobacco plants expressing the part of the ARGOS gene in antisense orientation were characterized by a reduction in the level of the NtEXPA1 and NtEXPA4 gene expression.

Four putative orthologs of the AINTEGUMENTA gene were found in the poplar (Populus trichocarpa) genome. Two of them, which we called PnANTL1 and PnANTL2, were isolated from black poplar (Populus nigra L.) and transgenic tobacco plants were generated on their basis. Tobacco plants that were transgenic for the PnANTL1 gene were characterized by increased leaf length, smaller flower size, and different defects in the development of the corolla and stamens. Tobacco plants that were transgenic for the PnANTL2 gene were characterized by an increased length of leaves and larger flowers. The increase in the leaf size in all transgenic plants was determined by stimulation of cell expansion; the number of cells was even reduced in the case of the PnANTL1 gene. Ectopic expression of the PnANTL1 and PnANTL2 genes promoted an increase in the level of mRNA of some tobacco expansins. The data we obtained demonstrate the involvement of transcription factors of the AP2 subfamily in the regulation of cell expansion.

M129V polymorphism of prion protein gene PRNP has been studied in patients with multiple sclerosis (MS) and healthy ethnic Russians from Bashkortostan using allele-specific PCR. The genotype frequency distribution of the examined polymorphism in Russians from Bashkortostan was similar to that in European populations. MM, MV, and VV genotype frequencies in control group and in the MS patients were 50.24%, 42.58%, 7.18% and 43.33%, 45.83%, 10.84%, respectively. It was shown that in the group of MS patients with onset of the disease at the age of 21 and older, the frequency of the VV genotype was higher than in the control group (14.3% versus 6.18%, respectively, P = 0.041). We suggest that the VV genotype is associated with higher risk factor of MS development in the patients aged 21 years and older.

Amplification and cloning of dahlia mosaic virus promoter were carried out for the first time. Sequence analysis showed homology between this promoter and the promoters of other caulimoviruses. In addition, amplification and cloning of the carnation etched ring virus promoter was performed.

The process of accumulation of knowledge on wheat and related wild species during the 20th century is briefly reviewed with special reference to the evidence of the recent years on evolution of polyploid wheats and the role of diploid species. The latter serve as potential donors of the genomes, detection of which is particularly important because of the continuing speciation in the tribe Triticeae and artificial development of synthetic forms. The arguments in favor of the donor role for various diploid wheat species and aegilopses from the section Sitopsis are compared. It is stated that in the formation of the both lines of polyploid wheats turgidum-aestivum and timopheevi, diploid Aegilops speltoides acted as a maternal form. In addition to plasmatic genomes, this aegilops species introduced into them also the B and G nuclear subgenomes. A comparison of nucleotide sequences in the variable part of the promoter of evolutionary conserved rRNA genes in polyploid wheats with their counterparts in diploid wheats and aegilopses confirmed the accepted wheat phylogenies.

Polymerase chain reaction (PCR) was used to study the frequencies of the gene of a low-molecular-weight alanine-rich cold shock protein in plants of temperate climate. This gene was demonstrated to be specific for the family Cruciferae. Its variability in this family was studied.

The nucleotide sequences of 280-360-bp domains of lectin genes from 20 legume species belonging to 17 genera have been determined. A computer analysis of the sequences has been performed with the LASERGENE package. Based on this analysis, we constructed the phylogenetic tree of the lectins, which reflects their phylogenetic and evolutionary relationships, and predicted the amino-acid sequences of the corresponding protein domains. Features of the structure of the hydrocarbon-binding lectin domains were elucidated in some species of legume genera from the temperate climatic zone. The domains were highly variable and contained the consensus sequence AspTrePheXxxAsxXxxXxxTrpAspProXxxXxxIns/DelArgHis bearing the bulk of amino acid replacements, insertions, and deletions. An association between legume groups (including species from different genera and tribes) symbiotic with the same rhizobium species and the similarity between the hydrocarbon-binding domains of lectins from these plants was found.

In diploid wheat Triticum monococcum L., a novel family of AT-rich repeated DNA sequences arranged in clusters of tandem arrays of 560-bp fragments is described. The nucleotide sequence of a 556-bp repeat unit was determined. The basic structural unit of this repeated DNA family contains subrepeats with the main motif AAACATTGTTAC. This type of repetitive DNA sequence could evolve via tandem amplification of short subrepeats with some subsequent divergence, and/or via recombination with unique sequences. Structural organization of homologous sequences, revealed by blot hybridization in other representatives of the Triticeae tribe, suggest that this family of repeated DNA is genome-specific.

In the intergenic spacer (IGS) of rDNA of diploid wheats Triticum urartu, T. boeoticum, and T. monococcum, the uncommon motives adjacent to the site of transcription initiation (TIS) are revealed. They are located in the region from -6 to +1 relative to the putative TIS and are not encountered in cereals studied earlier. In T. urartu and T. boeoticum, the motif TACTATG has been revealed, in T. monococcum--TATTATG, while diploid Aegilops speltoides has the motif TATAGTA, typical of the remaining cereal species. The TIS-surrounding rDNA IGS region of diploid wheats was compared to the correspondent known rDNA IGS regions of different plant and animal species.