[HEMK-Like Methyltransferases in the Regulation of Cellular Processes].

Human translational methyltransferase (methylase) HEMK2, whose orthologues are found in many prokaryotes and eukaryotes, methylates such diverse substrates as glutamine and lysine residues in proteins, deoxyadenosine in DNA, and arsenicals. One of the important substrate of HEMK2 methylase is a glutamine residue in the GGQ ultra-conservative motif of the eukaryotic release factor 1 (eRF1). Release factor methylation by HEMK2 orthologs is conserved among eukaryotes, archaea, and bacteria, although bacterial release factors differ in sequence and structure from eukaryotic ones. In this review, we consider the features of human HEMK2 methylase and its orthologs as multifunctional enzymes that regulate cellular processes, in particular, protein biosynthesis.

[The Influence of A/G Composition of 3' Stop Codon Contexts on Translation Termination Efficiency in Eukaryotes].

Translation termination is a finishing step of protein biosynthesis. The significant role in this process belongs not only to protein factors of translation termination but also to the nearest nucleotide environment of stop codons. There are numerous descriptions of stop codons readthrough, which is due to specific nucleotide sequences behind them. However, represented data are segmental and don't explain the mechanism of the nucleotide context influence on translation termination. It is well known that stop codon UAA usage is preferential for A/T-rich genes, and UAG, UGA-for G/C-rich genes, which is related to an expression level of these genes. We investigated the connection between a frequency of nucleotides occurrence in 3' area of stop codons in the human genome and their influence on translation termination efficiency. We found that 3' context motif, which is cognate to the sequence of a stop codon, stimulates translation termination. At the same time, the nucleotide composition of 3' sequence that differs from stop codon, decreases translation termination efficiency.

[In silico Analyses of Transcriptomes of the Marine Green Microalga Dunaliella tertiolecta: Identification of Sequences Encoding P-type ATPases].

De novo assembled transcriptomes of the marine microalga Dunaliella tertiolecta (Chlorophyta) were analyzed. Transcriptome assemblies were performed using short-read RNA-seq data deposited in the SRA database (DNA and RNA Sequence Read Archive, NCBI). A merged transcriptome was assembled using a pooled RNA-seq data set. The goal of the study was in silico identification of nucleotide sequences encoding P-type ATPases in D. tertiolecta transcriptomes. P-type ATPases play a considerable role in the adaptation of an organism to a variable environment, and this problem is particularly significant for microalgae inhabiting an environment with an unstable ionic composition. Particular emphasis was given to searching for a sequence coding Na^(+)-ATPase. This enzyme is expected to function in the plasma membrane of D. tertiolecta like in some marine algae, in particular, in the closely related alga Dunaliella maritima. An ensemble of 12 P-type ATPases consisting of members belonging to the five main subfamilies of the P-type ATPase family was revealed in the assembled transcriptomes. The genes of the following P-type ATPases were found: (1) heavy metal ATPases (subfamily PIB); (2) Ca^(2+)-ATPases of SERCA type (subfamily P2A); (3) H^(+)-ATPases (subfamily P3); (4) phospholipid-transporting ATPases (flippases) (subfamily P4); (5) cation-transporting ATPases of uncertain specificities (subfamily P5). The presence of functional Na^(+)-ATPases in marine algae is presently undoubted. However, contrary to expectations, we failed to find a nucleotide sequence encoding a protein that could unequivocally be considered a Na^(+)-ATPase. Further study is necessary to elucidate the roles of in silico revealed D. tertiolecta ATPases in Na^(+) transport.

Cloning and Functional Analysis of SaCLCc1, a Gene Belonging to the Chloride Channel Family (CLC), from the Halophyte Suaeda altissima (L.) Pall.

One of the genes of the CLC (Chloride Channel) family, SaCLCc1, from the halophyte Suaeda altissima (L.) Pall. was cloned. To investigate the function of SaCLCc1, it was expressed in the S. cerevisiae deletion mutant Δgef1::LEU2 for the only gene of the CLC family in this organism. The growth of the transformed SaCLCc1-expressing mutant Δgef1 was restored when cells were grown in Fe2+-deficient YPEG medium, in minimal synthetic media SD and SR (pH 7.0), and in rich YPD medium containing Mn2+. The complementation of the Δgef1 mutant phenotype with the SaClCc1 gene indicates the involvement of the SaClCc1 protein in the transport of Cl- ions.

Molecular cloning and characterisation of SaCLCa1, a novel protein of the chloride channel (CLC) family from the halophyte Suaeda altissima (L.) Pall.

The SaCLCa1 gene, a putative orthologue of AtCLCa, the Arabidopsis thaliana gene encoding a NO3-/H+ antiporter, was cloned from the halophyte Suaeda altissima. It belonged to the CLC family, comprising anionic channels and anion/H+ antiporters. SaCLCa1 ion specificity was studied by heterologous expression of this gene in Saccharomyces cerevisiae GEF1 disrupted strain, Δgef1, where GEF1 encoded the only CLC family protein, the Cl- transporter Gef1p, in undisrupted strains of this organism. For comparison, the function of another recently identified S. altissima CLC family gene, SaCLCc1, was also characterised. Expression of SaCLCc1 in Δgef1 cells restored their ability to grow on selective media. This supported the chloride specificity of this transporter. By contrast, expression of SaCLCa1 did not complement the growth defect phenotype of Δgef1 cells. However, growth of the Δgef1 mutant on the selective media was partially restored when it was transformed with SaCLCa1(C562 T), encoding the modified protein SaCLCa1(P188S), in which proline responsible for NO3- selectivity in selective filter was replaced by serine providing chloride selectivity. Quantitative real-time polymerase chain reactions (qRT-PCR) showed that significant induction of SaCLCa1 occurred in the roots of S. altissima when plants were grown on nitrate-deficient medium, while SaCLCc1 activation was observed in S. altissima leaves of plants grown in increasing Cl- concentrations of nutrient solution. These results suggested that SaCLCa1 and SaCLCc1 function as anionic transporters with nitrate and chloride specificities, respectively.

[Genetic constitution differences in patients with various forms of alcoholism]. / Genetiko-konstitutsional'nye razlichiia bol'nykh s raznymi formami alkogolizma.

Four groups of alcoholics were identified, according to the structure of psychopathological disturbances outside the acute period of abstinence and progression of the disease. There were inter-group differences in the level of familial history of alcoholism, alcoholic psychoses and psychic diseases, as well as in the mean values of some parameters of dermatoglyphics of palms, colour perception and taste perception of phenylthiocarbamide. The used clinical criteria of patients' distribution reflect the constitutional-genetic differences between them, which should be taken into consideration in developing differential pharmacotherapy.