[Association of Polymorphic Genome Variants in the 2q32.1 Locus with the Development of Vasovagal Syncope].

The vasovagal syncope (VVS) is the most common form of syncope. The mechanisms of VVS development are not entirely clear. It is known that there is a genetic predisposition to this disease, but the data on the roles of individual genes are quite contradictory. Recently, a genome-wide association study identified a locus at chromosome 2q32.1 associated with a united group of diseases, that is, syncope and collapse; among the single nucleotide polymorphisms (SNPs) of this locus, the most significant association was observed for rs12465214. In a homogeneous sample of patients diagnosed with VVS, we analyzed the association of rs12465214, rs12621296, rs17582219 and rs1344706 located on chromosome 2q32.1 with this form of syncope. In the enrolled set, only rs12621296 was associated with VVS by itself, whereas associations of other SNPs were observed only in biallelic combinations. An epistatic interaction between the components of the combination rs12621296*A + rs17582219*A was revealed. The possible involvement of individual genes on the 2q32.1 locus in the genetic architecture of the VVS is discussed.

[Risk of Multiple Sclerosis: Analysis of Interactions Between Variants of Nuclear and Mitochondrial Genomes].

There is increasing evidence that the interaction of the mitochondrial and nuclear genomes substantially affects the risk of neurodegenerative diseases. The role of mitonuclear interactions in the development of multiple sclerosis, a severe chronic neurodegenerative disease of a polygenic nature, is poorly understood. In this work, we analyzed the association of multiple sclerosis with two-component mitonuclear combinations that include each of seven polymorphic variants of the nuclear genome localized in the region of the UCP2, and KIF1B genes and in the PVT1 locus (MYC, PVT1, and MIR1208 genes) and each often polymorphisms of the mitochondrial genome, as well as individual genetic variants that make up these combinations. Association of the individual components of these combinations with multiple sclerosis was also evaluated. 507 patients with multiple sclerosis and 321 healthy individuals were enrolled in the study, all participants were ethnic Russians. Two mitonuclear combinations associated with multiple sclerosis were identified: the UCP2 (rs660339)*A + MT-ATP6 (rs193303045)*G combination was characterized by p-value = 0.015 and OR= 1.39 [95% CI 1.05-1.87], and the PVT1 (rs2114358)*G + MT-ND1 (rs1599988)*С combination - by p-value = 0.012 and OR = 1.77 [95% CI 1.10-2.84]. Only one of the individual components of these combinations, allele rs660339*A of the nuclear gene UCP2 encoding uncoupling protein 2 of the mitochondrial anion carrier family, was independently associated with multiple sclerosis (p = 0.028; OR = 1.36 [95% CI 1.01-1.84]). This study expands the current understanding of the role of mitonuclear interactions and variance of nuclear genes, whose products function in mitochondria, and in risk of MS.

[The role of mitochondria in pathological mechanisms of innate immunity in multiple]. / Rol' mitokhondrii v realizatsii patologicheskikh mekhanizmov vrozhdennogo immuniteta pri rasseyannom skleroze.

The review discusses the role of mitochondria in multiple sclerosis (MS). Previously, damage to the mitochondria was regarded as a manifestation of secondary damage to axons and neurons, i.e. as a marker of neurodenegation. Recently, the role of mitochondria in the early stages of MS development, when they could participate in the activation of innate immunity and trigger activation of autoimmune responses of acquired immunity, has been increasingly discussed. The role of polymorphism mitochondrial DNA changes in MS is discussed.

[Variability of the Mitochondrial Genome and Development of the Primary Progressing form of Multiple Sclerosis].

Recently, it has been shown that dysfunction of mitochondria is an important component of the molecular mechanisms of the development of many neurodegenerative diseases. These include multiple sclerosis, a chronic autoimmune and neurodegenerative disease of the central nervous system, which is characterized by clinical heterogeneity. The role of genetic variability of mitochondrial DNA in the development of various clinical forms of multiple sclerosis is poorly understood. The aim of present study was to analyze the association often mitochondrial DNA single nucleotide polymorphisms and the nine most common European mitochondrial haplogroups (H, J, K, U, T, I, V, W and X) with a severe and relatively rare multiple sclerosis disease form-primary progressive multiple sclerosis. 110 patients with primary progressive multiple sclerosis and 406 healthy controls were enrolled in the study, all ethnic Russians. For the first time association of the m.12308*G (rs2853498) variant (P = 0.024) and haplogroup U (P = 0.0004, passes the adjustment for multiple comparisons: Pcorr = 0.0076) with primary progressive multiple sclerosis was shown. Comparison of these data with the results of our previous study [1], that was focused on the role of mitochondrial genome variability in susceptibility to the most common form of multiple sclerosis, relapsing-remitting multiple sclerosis, leads to the conclusion that two different mitochondrial haplogroups, U and J, are involved in the development of two different clinical forms of multiple sclerosis. The results may contribute to the identification of new targets for the treatment of primary progressive multiple sclerosis, for which there is no effective pathogenetic treatment at the moment.

Involvement of Mitochondria in Neurodegeneration in Multiple Sclerosis.

Functional disruption and neuronal loss followed by progressive dysfunction of the nervous system underlies the pathogenesis of numerous disorders defined as "neurodegenerative diseases". Multiple sclerosis, a chronic inflammatory demyelinating disease of the central nervous system resulting in serious neurological dysfunctions and disability, is one of the most common neurodegenerative diseases. Recent studies suggest that disturbances in mitochondrial functioning are key factors leading to neurodegeneration. In this review, we consider data on mitochondrial dysfunctions in multiple sclerosis, which were obtained both with patients and with animal models. The contemporary data indicate that the axonal degeneration in multiple sclerosis largely results from the activation of Ca2+-dependent proteases and from misbalance of ion homeostasis caused by energy deficiency. The genetic studies analyzing association of mitochondrial DNA polymorphic variants in multiple sclerosis suggest the participation of mitochondrial genome variability in the development of this disease, although questions of the involvement of individual genomic variants are far from being resolved.

Variants of Mitochondrial Genome and Risk of Multiple Sclerosis Development in Russians.

For the first time in the history of ethnic Russians, an association analysis the development of multiple sclerosis (MS) was performed for the mitochondrial haplogroups H, J, K, and U, as well as for the individual mitochondrial DNA (mtDNA) polymorphisms discriminating these haplogroups (m.1719G > A, m. 7028C > T, m.9055G > A, m.10398A > G, m.12308A > G). A total of 283 unrelated patients with the relapsing-remitting form of MS and 290 healthy controls were enrolled in the study. Association of haplogroup J with MS was observed (P = 0.0055, OR = 2.00 [95% CI 1.21-3.41]). After gender stratification, the association remained significant in women (P = 0.0083, OR = 2.20 [95% CI 1.19-4.03]). A multilocus analysis of the association between combinations of mtDNA haplogroups with variants of 38 nuclear immune-related genes and MS risk was carried out. MS-associated biallelic combinations of haplogroup J with the alleles CCL5 rs2107538*A, PVT1 rs2114358*G, TNFSF14 rs1077667*C, and IL4 rs2243250*C, which were not associated with MS individually, were identified. For the combination of haplogroup J and the CCL5*A allele (P = 0.00043, OR = 5.47 [95% CI 1.85-16.15]), a epistatic (synergistic) interaction between the components was established using two statistical criteria: the PFLINT value in the Fisher-like interaction numeric test and the synergy factor, SF (PFLINT = 0.025, SF = 4.32 [95% CI 1.20-15.60]). The combination of haplogroup J and the PVT1*G allele is characterized by PFLINT = 0.084; SF = 3.05 [95% CI 1.00-9.31] and can also be epistatic. Thus, interaction between nuclear and mitochondrial genome components in the risk of developing MS was demonstrated for the first time.

ATP-dependent DNA ligase from Thermococcus sp. 1519 displays a new arrangement of the OB-fold domain.

DNA ligases join single-strand breaks in double-stranded DNA by catalyzing the formation of a phosphodiester bond between adjacent 5'-phosphate and 3'-hydroxyl termini. Their function is essential for maintaining genome integrity in the replication, recombination and repair of DNA. High flexibility is important for the function of DNA ligase molecules. Two types of overall conformations of archaeal DNA ligase that depend on the relative position of the OB-fold domain have previously been revealed: closed and open extended conformations. The structure of ATP-dependent DNA ligase from Thermococcus sp. 1519 (LigTh1519) in the crystalline state determined at a resolution of 3.02 Šshows a new relative arrangement of the OB-fold domain which is intermediate between the positions of this domain in the closed and the open extended conformations of previously determined archaeal DNA ligases. However, small-angle X-ray scattering (SAXS) measurements indicate that in solution the LigTh1519 molecule adopts either an open extended conformation or both an intermediate and an open extended conformation with the open extended conformation being dominant.

Structure of a beheaded 30 S ribosomal subunit from Thermus thermophilus.

The 22 S ribonucleoproten particles containing the 5' (body) and the central (platform) domains of the Thermus thermophilus 30 S subunit has been studied by sedimentation, neutron scattering and electron microscopy. The RNP particles have been obtained by oligonucleotide-directed cleavage of 16 S RNA with ribonulease H in the region of the 900th nucleotide of the protein-deficient derivatives of the 30 S subunits. It is shown that these RNP particles are very compact, though their form and dimensions differ slightly from those expected from the electron microscopy model of the 30 S subunit beheaded by computer simulation. The particles are subdivided into two structural domains whose mutual arrangement differs from that of the corresponding morphological parts of the native 30 S subunit. Electron microscopy demonstrates that the mutual arrangement of domains in the RNP particles is not strictly fixed suggesting that interaction with the third domain of the 30 S subunit is a requisite for their correct fitting.

A model of the quaternary structure of the Escherichia coli F1 ATPase from X-ray solution scattering and evidence for structural changes in the delta subunit during ATP hydrolysis.

The shape and subunit arrangement of the Escherichia coli F1 ATPase (ECF1 ATPase) was investigated by synchrotron radiation x-ray solution scattering. The radius of gyration and the maximum dimension of the enzyme complex are 4.61 +/- 0.03 nm and 15.5 +/- 0.05 nm, respectively. The shape of the complex was determined ab initio from the scattering data at a resolution of 3 nm, which allowed unequivocal identification of the volume occupied by the alpha3beta3 subassembly and further positioning of the atomic models of the smaller subunits. The delta subunit was positioned near the bottom of the alpha3beta3 hexamer in a location consistent with a beta-delta disulfide formation in the mutant ECF1 ATPase, betaY331W:betaY381C:epsilonS108C, when MgADP is bound to the enzyme. The position and orientation of the epsilon subunit were found by interactively fitting the solution scattering data to maintain connection of the two-helix hairpin with the alpha3beta3 complex and binding of the beta-sandwich domain to the gamma subunit. Nucleotide-dependent changes of the delta subunit were investigated by stopped-flow fluorescence technique at 12 degrees C using N-[4-[7-(dimethylamino)-4-methyl]coumarin-3-yl]maleimide (CM) as a label. Fluorescence quenching monitored after addition of MgATP was rapid [k = 6.6 s-1] and then remained constant. Binding of MgADP and the noncleavable nucleotide analog AMP . PNP caused an initial fluorescent quenching followed by a slower decay back to the original level. This suggests that the delta subunit undergoes conformational changes and/or rearrangements in the ECF1 ATPase during ATP hydrolysis.

Solution scattering structural analysis of the 70 S Escherichia coli ribosome by contrast variation. II. A model of the ribosome and its RNA at 3.5 nm resolution.

Selectively deuterated 70 S E. coli ribosomes and isolated 30 S and 50 S subunits were analyzed by X-ray and neutron solution scattering. The resulting contrast variation data set (42 curves in total) was proven to be consistent in describing the ribosome as a four-phase system composed of the protein and rRNA moieties of both subunits. This data set thus provides ten times more information than a single scattering curve. A solid body four-phase model of the 70 S ribosome at low resolution was built from the envelope functions of the 30 S and 50 S subunits and of those of the corresponding RNA moieties. The four envelopes were parameterized at a resolution of 3.5 nm using spherical harmonics and taking into account interface layers between the phases. The initial approximation for the envelopes of the subunits was taken from electron microscopic data presented recently by J. Frank and co-workers (Albany); the rRNA envelopes were initially approximated by spheres. The optimization and the refinement of the model proceeded by non-linear least squares minimization fitting the available experimental data. The refined envelopes of the subunits differ by about 10% from the starting approximation and the shape of the final 70 S model lies between the outer envelopes of the models by Frank and by M. von Heel & R. Brimacombe (Berlin). The rRNA moiety in the 30 S subunit is more anisometric than the subunit itself, whereas the rRNA of the 50 S subunit forms a compact core. The rRNAs protrude to the surfaces of the subunits and occupy approximately 30 to 40% of the corresponding surface areas. X-ray scattering curves of the two main functional elongation 70 S complexes (pre- and post-translocational) differ only marginally from those of the non-programmed ribosomes, suggesting that the low resolution four-phase model is also valid for the elongating 70 S ribosome.

Solution scattering structural analysis of the 70 S Escherichia coli ribosome by contrast variation. I. Invariants and validation of electron microscopy models.

Solutions of selectively deuterated 70 S Escherichia coli ribosomes and of free 30 S and 50 S subunits were studied by neutron scattering using contrast variation. The integrity of the partially deuterated particles was controlled by parallel X-ray measurements. Integral parameters of the entire ribosome, of its subunits and of the protein and rRNA moieties were evaluated. The data allow an experimental validation of the two most recent electron microscopy reconstructions of the 70 S ribosome presented by the groups of J. Frank (Albany) and of M. van Heel & R. Brimacombe (Berlin). For each reconstruction, integral parameters and theoretical scattering curves from the 70 S and its subunits were calculated and compared with the experimental data. Although neither of the two models yields a comprehensive agreement with the experimental data, Frank's model provides a better fit. For the 50 S subunit of van Heel & Brimacombe's model the fit with the experimental data improves significantly when the internal channels and tunnels are filled up. The poorer fit of the latter model is thus caused by its "sponge"-like structure which may partly be due to an enhancement of high frequency contributions in some of the steps of the three-dimensional image reconstruction. It seems therefore unlikely that the ribosome has a "sponge"-like structure with a pronounced network of channels.