Vol 54, No 8 (2018)

A majority of mammalian and human protein-coding genes undergo alternative splicing with the formation of mRNA isoforms. It was established that 30−40% of the formed mRNA isoforms fell into a special category of bifunctional molecules, “coding−noncoding RNAs.” One possible explanation for the presence of such a large number of unproductive mRNAs is that these molecules are involved in basic processes of gene expression regulation. In this review, the concept of regulated unproductive splicing and translation is considered, which implies a close relationship between the processes of alternative splicing, formation of noncoding mRNA isoforms, and their subsequent degradation, which determines the proportion of productive mRNA transcripts of a gene and the level of its expression in the cell. Modern concepts of noncoding mRNA isoforms of protein-coding genes and their role in the regulation of gene expression under certain physiological and pathophysiological conditions are presented.

Epigenetic effects are considered as a mechanism of the emergence of new inherited traits with their transmission between generations through meiosis. Modern genomic evaluation does not explain the entire phenotypic variance of traits. It is quite obvious that a significant part of the unaccounted dispersion reflects epigenetic effects carried out through DNA methylation, histone and chromatin modifications, and activity of noncoding types of RNA. Epigenetic effects could potentially be used in breeding programs. The obtained data testify to the significant role of epigenetic factors in the expression of imprinting genes, cellular processes, development of muscle tissue, and fat metabolism in animals. The ability of various additives in the diet to induce epigenetic modifications with phenotypic variability has been convincingly proven. However, there are still many contradictions and limitations in the justification of the hereditary component of epigenetics for introduction into animal breeding. Development of modern technologies, such as chromatin immunoprecipitation with microchips of DNA (ChIP-Chip), next-generation sequencing (ChIP-Seq), and epigenomic editing based on CRISPR-Cas9, gives grounds for optimism in solving problems of introducing epigenetic phenomena in livestock breeding.

This study has shown for the first time that deuterium oxide (D₂O) enhances expression of the E. coli ada-regulon induced by alkylating compounds, N-nitroso-N-methylurea (NMU) and methyl methanesulfonate (MMS). To compare the induction of ada-regulon in deuterated and in non-deuterated (control) cultures of E. coli, a biosensor based on the E. coli strain K12 MG1655 (pAlkA–lux) luminescing as a result of activating the alkA gene promoter in response to DNA alkylation was used. Depending on the D₂O concentration from 5 to 10% in the pre-deuterium medium, these alkylating compounds at a concentration of 0.005 M induced expression of the alkA gene from 1.3 to 5 times higher as compared to induction in nondeuterated culture. It is suggested that deuterium can be one of the main factors in stabilizing the bond between the promoter and the alkylated Ada protein, leading to increased transcription of the ada-regulon.

Identification and analysis of the melanin biosynthesis gene in the Sinorhizobium meliloti CA15-1 strain were carried out. Tn5 mutants, which lost the ability to synthesize melanin, were obtained. Molecular biological analysis of the mepA gene encoding tyrosinase was performed. In contrast to other members of the Rhizobiacea group, the identical structure of the mepA locus was revealed for all strains of nodule bacteria of the Sinorhizobium genus. Phylogenetic analysis indicated that horizontal transfer of the mepA gene occurred in the course of evolution of bacterial tyrosinases. At the same time, the closely related members of nodule bacteria “acquired” this gene from different sources. Analysis of symbiotic properties of the Mep^– mutants of the CA15-1 strain showed that melanin did not affect the ability to go into an efficient symbiosis with alfalfa. Most probably, it is important only at the stages of adaptation of the free-living cells in the environment.

The variability of the nucleotide sequences of the fragment of the COI gene of the female genome was studied in four phenotypic groups of the Black Sea mollusk Mytilus galloprovincialis. It was shown that the parameters of genomic diversity (the number of haplotypes, haplotypic and nucleotide diversity, and the number of nucleotide substitutions, including pairwise ones) in mussels with dark shell color are significantly higher than in individuals with light color phenotypes. The revealed differences are related to the peculiarities of ecological preferences of mussels with dark and light shells.

Matrix metalloproteinases play an important role in the pathogenesis of psoriasis. The aim of this paper was to explore the influence of MMP1 silencing with a specific shRNA on migration and proliferation of epidermal keratinocytes exposed to tumor necrosis factor, as well as changes in the expression of genes involved in their terminal differentiation. Changes in gene expression were analyzed by real-time PCR. The cell proliferation was assessed by comparative analysis of the growth curves. The cell migration was explored by scratch assay. To quantify cell migration, the representative areas of cell cultures were photographed in the equal periods of time and compared to each other. The obtained results demonstrated that an exposure of control cell line to tumor necrosis factor caused changes in the expression of several genes similar to ones that were previously observed in lesional psoriatic skin. Particularly, the expression of MMP9, IVL and KRT16 increased whereas the expression of LOR, KRT1 and-10—decreased. In contrast, MMP1-deficient cells treated with tumor necrosis factor exhibited higher levels of LOR, KRT1 and -10, as well as lower levels KRT16 and -17 compared to control cells treated with the same cytokines. Moreover, MMP1-deficient cells exhibited a lower level of CCNА2 and higher level of CCND1. In this respect, knocking MMP1 down resulted in a lower cell proliferation and migration rates of TNF-treated epidermal keratinocytes. In conclusion, this study demonstrated that MMP1 silencing with specific shRNA can be beneficial for psoriasis. We found that knocking MMP1 down has an antiproliferative effect on epidermal keratinocytes and partially normalizes the expression of cyclins CCNA2, and -D1, as well as the genes involved in the terminal differentiation of this kind of cells (LOR, KRT1, -10, -16 and -17).

Noonan syndrome (NS) is a very rare heterogenous genetic disorder often characterized by short stature, facial dysmorphisms, congenital heart defects and learning disabilities in affected children. In the current study, we sought to discover the disease causal mutations, inherited or de novo, for Noonan Syndrome among Arab patients. We screened the coding regions and splice sites of 10 known RAS/MAP Kinase pathway genes in 17 NS-trios and 100 random healthy volunteers by oilgonucleotide chip testing and Sanger sequencing methods. We found pathogenic heteroallelic de novo mutations in BRAF or PTPN11 gene in 7/17 (41.17%) of NS patients. None of the 200 chromosomes of healthy volunteers had those pathogenic mutations. Genotype-phenotype analysis showed positive correlation between BRAF and PTPN11 gene mutations and classical NS clinical manifestations. Characteristic facies is the major observed clinical manifestation among PTPN11-mutation positive cases (c.236A>G, c.854T>C, c.923A>G), whereas both characteristic facies and ectodermal manifestations are seen as dominant clinical features among BRAF-mutation positive cases (c.730A>C, c.770A>G, c.1406G>A). In addition to genotyping and clinical phenotyping, we performed computational structural analysis to examine the impact of amino acid substitution mutations on the conformation and folding of BRAF and PTPN11 proteins. Our results suggested that BRAF (c.730A>C, c.770A>G, c.1406G>A) and PTPN11 (c.236A>G, c.854T>C, c.923A>G) gene mutations elicits structural and functional alterations at protein level, which would eventually lead to dysregulation of RAS-MAPK signaling cascade, which plays critical a role in cell cycle and senescence. In conclusion, our study suggest that molecular screening of BRAF and PTPN11 genetic mutations in Arab NS patients may assist in deriving competitive outcomes related to clinical phenotyping and disease diagnosis.

Plants of the genus Linaria are scientifically interesting owing to the presence of natural-transgenic forms containing a set of agrobacterial genes (so-called cT-DNA). Many Linaria species are valuable ornamental plants. However, until recently, the literature did not describe the method of genetic transformation of plants of the genus Linaria. In this paper, we present the method of in vitro agrobacterial transformation of plants of Moroccan toadflax (Linaria maroccana Hook. f.). Method of adaptation for in vivo conditions is also described. This technique will be used in further studies of the functioning of сT-DNA and can also be recommended for solving applied problems.

The variety of common spring wheat Chelyaba 75 carries a translocation from Aegilops speltoides Tausch in the chromosome 2D, which contains the leaf rust resistance gene and gametocidal genes. The length of this translocation was determined by molecular-genetic analysis. It is shown that the long arm of chromosome 2D is completely replaced by the long arm of chromosome 2S; it is possible that translocation involves the near-centromere region of the short arm. According to molecular analysis data, the translocation from Ae. speltoides in the Chelyaba 75 variety differs from the 2S chromosome region carrying the Lr35/Sr39 genes. This makes it possible to designate the leaf rust resistance gene of the Chelyaba 75 as LrSp2. The inheritance of LrSp2 in four populations from crossing Chelyaba 75 with different varieties of common wheat was studied. Estimation of leaf rust resistance of F₂ and F₃ hybrids in field conditions (2015–2016) revealed the absence of susceptible plants. The presence of 2DS.2SL translocation in hybrid plants was confirmed by molecular analysis. The results indicate the action of the gametocidal gene localized in the 2DS.2SL translocation and the fact that its tight linkage to the LrSp2 gene is inherited in a series of generations.