Depressive disorder (DD) is a widespread mental disorder. Although DD is to some extent inherited, the genes contributing to the risk of this disorder and its genetic mechanisms remain poorly understood. A recent large-scale genome-wide association Chinese study revealed a strong association between the SIRT1 gene variants and DD. The aim of this study was to analyze the occurrence of heterozygote carriers and search for rare SNP variants of the SIRT1 gene in a cohort of DD patients as compared with a cohort of randomly selected members of the Russian population. The complete coding sequences of the SIRT1 gene from 1024 DNA samples from the general Russian population and from 244 samples from patients with DD were analyzed using targeted sequencing. Four new genetic variants of the SIRT1 were discovered. While no significant differences in the allele frequencies were found between the DD patients and the general population, differences between the frequencies of homozygote carriers of specific alleles and occurrences of heterozygous were found to be significant for rs2236318 (P < 0.0001), and putatively, rs7896005 (P < 0.05), and rs36107781 (P < 0.05). The study found for the first time that two new SNPs (i.e., 10:69665829 and 10:69665971) along with recently reported ones (rs773025707 and rs34701705), are putatively associated with DD. The revealed DD-associated SIRT1 SNPs might confer susceptibility to this disorder in Russian population of European descent.

We analyzed variability of the expression of three reference genes in biopsy samples of the olfactory epithelium obtained from healthy volunteers. The expression of B2M, HPRT1, and CASC3 genes was analyzed by real-time PCR. The pairs of genes B2M-HPRT1 and B2M-CASC3 were found to possess minimum individual variability of expression and can be reliable candidates for the reference genes in analysis of gene expression in neural cells.

BACKGROUND:Cystic fibrosis (CF) is one of the most common life-threatening genetic disorders. Around 2000 variants in the CFTR gene have been identified, with some proportion known to be pathogenic and 300 disease-causing mutations have been characterized in detail by CFTR2 database, which complicates its analysis with conventional methods.METHODS:We conducted next-generation sequencing (NGS) in a cohort of 89 adult patients negative for p.Phe508del homozygosity. Complete clinical and demographic information were available for 84 patients.RESULTS:By combining MLPA with NGS, we identified disease-causing alleles in all the CF patients. Importantly, in 10% of cases, standard bioinformatics pipelines were inefficient in identifying causative mutations. Class IV-V mutations were observed in 38 (45%) cases, predominantly ones with pancreatic sufficient CF disease; rest of the patients had Class I-III mutations. Diabetes was seen only in patients homozygous for class I-III mutations. We found that 12% of the patients were heterozygous for more than two pathogenic CFTR mutations. Two patients were observed with p.[Arg1070Gln, Ser466*] complex allele which was associated with milder pulmonary obstructions (FVC 107 and 109% versus 67%, CI 95%: 63-72%; FEV 90 and 111% versus 47%, CI 95%: 37-48%). For the first time p.[Phe508del, Leu467Phe] complex allele was reported, observed in four patients (5%).CONCLUSION:NGS can be a more information-gaining technology compared to standard methods. Combined with its equivalent diagnostic performance, it can therefore be implemented in the clinical practice, although careful validation is still required.

Wilson's disease (WD, OMIM # 277900), or hepatolenticular degeneration, is an autosomal recessive disease caused by a large number of different mutations in the ATP7B gene. More than 700 different mutations in the coding sequence of ATP7B have been described so far. Several studies provide information about specific mutations' frequencies in WD patients in Russia. However, there is no direct data on overall ATP7B mutation frequencies among Russian citizens. In this study, we used the NGS Ion Torrent platform to identify mutations in the ATP7B gene in a random sample of the Russian population. We performed analysis of coding sequences of the ATP7B gene for 962 people from the general population of the Novosibirsk region. Frequency of mutations with clinical significance was found to be 0.93%. The most frequent mutations with clinical significance were His1069Gln (0.62%) and Glu1064Lys (0.31%). Analysis of the spectrum and prevalence of mutations in the Russian population revealed a pattern similar to other countries with predominantly Caucasian populations.

Advances in DNA sequencing technologies have led to an avalanche-like increase in the number of gene sequences deposited in public databases over the last decade as well as the detection of an enormous number of previously unseen nucleotide variants therein. Given the size and complex nature of the genome-wide sequence variation data, as well as the rate of data generation, experimental characterization of the disease association of each of these variations or their effects on protein structure/function would be costly, laborious, time-consuming, and essentially impossible. Thus, in silico methods to predict the functional effects of sequence variations are constantly being developed. In this review, we summarize the major computational approaches and tools that are aimed at the prediction of the functional effect of mutations, and describe the state-of-the-art databases that can be used to obtain information about mutation significance. We also discuss future directions in this highly competitive field.

Mutations at BRAF codon V600 are used as predictive biomarkers for targeted therapy of skin melanoma. Here, a simple sensitive test to detect mutations of BRAF-V600 was developed using real-time PCR with allele-specific primers and TaqMan probes. Two versions of the test using sense and antisense allele-specific primers were designed and evaluated. The test detected 1% mutant allele V600E/K in 10 ng DNA standard made from wild-type human DNA spiked with BRAF-V600E or the V600K plasmid. The test was validated on clinical formalin-fixed paraffin-embedded samples of skin melanoma using pyrosequencing as a reference method. In the clinical samples, we detected the common mutation V600E, as well as the rare mutations V600K, V600E2 (codon GAA), V600E2 K601del, V600D-K601del, and V600R. In comparison with pyrosequencing, both versions of the test had 100% specificity with sensitivities of 97 and 86% for sense and antisense allele-specific primers, respectively. Using the PCR test with sense allele-specific primers, mutations in V600 were found in 33 of 51 Russian patients (64.7%) with cutaneous melanoma. This closed-tube real-time PCR test can be used as a simple and sensitive assay for mutations of BRAF-V600 in cutaneous melanoma. (C) 2014 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

The frequencies of four mutations in the BRCA1 gene (185delAG, T300G, 4153delA, and 5382insC) were estimated in the Russian population. The mutations were analyzed in 7920 DNA samples obtained from randomly selected Novosibirsk citizens and 570 samples from breast cancer patients at Siberian hospitals. The mutations were detected by allele-specific real-time PCR. The mutation analysis was performed with pooled DNA samples to reduce the cost of the study. The 5382insC mutation was found in 20 of 7920 (0.25%) population DNA samples and in 14 of 570 (2.46%) breast cancer samples; the T300G mutation was detected in 4 population samples (0.05%) and in 2 breast cancer samples (0.35%); the 185delAG or 4153delA mutations were not identified in any of the 7920 samples and were detected in 1 (0.18%) breast cancer case each.

Two approaches to somatic point mutations in 12 and 13 codones of K-ras gene were analyzed: PCR/SSCP/ACRS/sequencing and allele-specific PCR in the real-life regimen (Russian set "KRAS-7M"). The comparison was carried out on 62 examples of genomic DNA extracted from frozen colon carcinomas, which underwent manual dissection. The results obtained in two attempts were consistent in 95,2% (N=59). Specificity and sensitivity of K-ras mutations detection using "KRAS-7M" set were 100 and 96,4% respectively, and 94,1 and 100% respectievly using PCR/SSCP/ACRS/automatic sequencing. False positive results were absent when detecting with "KRAS-7M" and accounted for 2 cases (5,9%) when using PCR/SSCP/ ACRS/automatic sequencing. The only false negative response (3,6%) was obtained analyzing mutations using "KRAS-7M".

A few founder BRCA1 mutations (5382insC, 4154delA, 185delAG) account for up to 15% of high-risk (young-onset or familial or bilateral) breast cancer (BC) cases in Russia. The impact of non-founder BRCA1 mutations in this country is less studied; in particular, there are no reports analyzing gross rearrangements of this gene in the Russian patient series. We selected for the study 95 founder mutation negative high-risk BC cases. Combination of high-resolution melting (HRM) and sequencing revealed six presumably BC-associated alleles (2080delA, 4808C>G, 5214C>T, 5236G>A, 5460G>T, 5622C>T) and one variant of an unknown significance (4885G>A). The pathogenic role of the 5236G>A mutation leading to G1706E substitution was further confirmed by the loss of heterozygosity analysis of the corresponding tumor tissue. Multiplex ligation-dependent probe amplification (MLPA) revealed two additional BRCA1 heterozygotes, which carried BRCA1 deletions involving exons 1-2 and 3-7, respectively. Based on the results of this investigation and the review of prior Russian studies, three BRCA1 mutations (2080delA, 3819del5, 3875del4) were considered with respect to their possible founder effect and tested in the additional series of 210 high-risk BC patients; two BRCA heterozygotes (2080delA and 3819del5) were revealed. We conclude that the non-founder mutations constitute the minority of BRCA1 defects in Russia.

Amplification of genes in breast cancer cells was shown to be coordinated in the majority of cases assuming the presence of common undisclosed mechanism underlying intrachromosomal gene amplification process. Overexpression and amplification of the HER-2/neu gene is observed in 20–30% of breast cancer cases and predicts more frequent relapse and shorter survival time. However, the initial events and molecular mechanisms of chromosomal aberrations in the region around HER2/neu as well as the precise boundaries of amplified regions remain to be obscure. This study was an attempt to define the boundaries of amplified chromosome 17q12-q21 region around HER2/neu gene. Structural peculiarities of amplification boundary regions were investigated by various techniques. Gene dosage analysis was performed for several genes located around HER2/neu gene in 154 breast cancer tissue samples. The copy number of the ppparbp, her2/neu, znfn1a3 Casc3 and top2a genes were analyzed by comparative TaqMan real time PCR. Fifty six samples (36 %) were found to be her2/neu-amplified (NHER2/neu ≥ 1,5), the boundaries for HER2-containing amplicons were mapped. Observed results suggest that similar positions of amplified region boundaries in different breast cancer samples are not accidental and may be related with the DNA structural and/or sequence peculiarities of boundary regions. Trying to find “special” sequences at the amplicon boundaries, we performed the analysis of sequence flexibility in the region TBC1D3– HER2/neu – TOP2A using the TwistFlex program. The analysis revealed several high flexible sequences in SOCS7, FBX047, HER2/neu and ZNFN1A3 genes. The locations of amplified region boundaries in 30% of cases were inside ZNFN1A3 gene. Organization of DNA sequence and nucleotide composition of FlexZNF-1 and FlexZNF-2 were similar to AT-rich islands of common fragile site (FS). Sequences of FlexZNF-1 and FlexZNF-2 have strong potential to form secondary structures according to the analysis by Mfold software (GCG Wisconsin PackageTM). Thus, the analysis of DNA sequence in TBC1D3– HER2/neu – TOP2A region revealed the existence of two flexible sequences in the ZNFN1A3 gene sequence with the strong potential to form stable secondary structures which may affect normal DNA replication at these sites and result in DNA double strand break appearance. The location of FlexZNF-1 and FlexZNF-2 strongly coincided with the location of amplified around HER2/neu gene fragment boundaries observed by real time PCR analysis. This observation indicates involvement of Flex sites in the process of intrachromosomal DNA amplification.

Although the probability of both parents being affected by BRCA1 mutations is not negligible, such families have not been systematically described in the literature. Here we present a large breast-ovarian cancer family, where 3 sisters and 1 half-sister inherited maternal BRCA1 5382insC mutation while the remaining 2 sisters carried paternal BRCA1 1629delC allele. No BRCA1 homozygous mutations has been detected, that is consistent with the data on lethality of BRCA1 knockout mice. This report exemplifies that the identification of a single cancer-predisposing mutation within the index patient may not be sufficient in some circumstances. Ideally, all family members affected by breast or ovarian tumor disease have to be subjected to the DNA testing, and failure to detect the mutation in any of them calls for the search of the second cancer-associated allele.

PCR assay with internal control was developed to quantify the her-2 gene dosage in human breast cancer tumor samples. Recombinant plasmid with a fragment of the her-2 gene containing the fragment of T7 phage DNA was designed especially to be used as an internal control in the PCR her-2 gene dosage assay. PCR conditions were optimized for the simultaneous usage of two templates--human genomic DNA and DNA of recombinant plasmid (internal control). The ability of the technology to discriminate a twofold increase of the her-2 gene dosage was demonstrated. Increased level of her-2 gene amplification was observed in 6 of 38 samples investigated. This new simple rapid assay can be an alternative to fluorescence in situ hybridization (FISH) and immunochemistry (ICH) tests for the detection of her-2 amplification in human tumors. This technique may be a useful tool for large randomized, prospective cooperative group trials and may support selection of optimal therapy for breast cancer patients in the future.

Oligonucleotide conjugates containing fluorescein residues in the sugar-phosphate back-bone were synthesized by the standard solid-phase phosphoramidite method using phosphor-amidites of 9-[2-deoxy-5- O -(4,4′-dimethoxytrityl)-2-methoxalylamino-β-D-ribofuranosyl]-and 9-[2-deoxy-5- O -(4,4′-dimethoxytrityl)-2-methoxalylamino-β-D-arabinofuranosyl]- N 6 -benzoyladenine. The relative efficiency of the oligonucleotide synthesis with modified phosphoramidites was estimated.

Phenobarbital-dependent protein binding was shown to occur to DNA fragments from the coding region of the cytochrome P450(BM-3) gene from Bacillus megaterium. Incubation of the DNA fragments from the coding region of the gene with total cell extract from Bacillus megaterium revealed two DNA regions with protein-binding capacity: +237/+318 and +319/+425 considering '0' as the start of cytochrome P450(BM-3) translation. DNaseI footprint analysis of the fragment +319/+425 with the total cell extract showed that some protein(s) protected DNA stretches from the position +373 up to the position +389 on the transcribed strand and from the position +378 up to the position +398 on the non-transcribed strand. DNaseI footprint analysis of the fragment +237/+318 revealed the protection in the region +262/+277 on the non-transcribed strand. Three regions protected by cell extract protein(s) from DNaseI hydrolysis (+262/+277, +373/+389 and +378/+398) appeared to be strongly homologous to the Barbie box sequence. Barbie-box-like sequences were found in the majority of regulatory regions of phenobarbital-inducible genes whose regulatory sequences had been reported (Fulco et al., 1994). Our results suggest that a functional role of Barbie box sequence takes place not only in regulatory but also in the coding region of the gene. In line with that hypothesis we analyzed all cytochrome P450 genes in respect to the presence of Barbie box-like sequences in their coding parts. At least one cytochrome P450 gene (CYP6A1, phenobarbital-inducible gene from Musca domestica) was shown to contain Barbie box sequence in the coding part of the gene.

Frequencies of alleles of the polymorphic locus D17S30 were estimated in a sample of 121 unrelated Siberian inhabitants of European origin. The main method of study was polymerase chain reaction (PCR). The consecutive use of two pairs of primers allowed increasing of the specificity and sensitivity of the amplification reaction. The results of this study may be of theoretical interest for studies in population genetics. They may also find practical application in forensic medical examination and,in the diagnosis of some genetic abnormalities.