Detection of Hypermethylation BRCA1/2 Gene Promotor in Breast Tumors Among Moroccan Women

Background: The promoter region is a key element of gene expression regulation. In mammals, most of the genes present, at the level of their promoter, a large number of islands CpG. Age is seen as another factor promoting breast cell cancer and the tumor stage. Aim: this study aimed to explore the hypermethylation of the BRCA1/2 promoter gene in breast cancer women and correlation with age and tumor stage.Materials and methods: fifty biopsies were derived from Moroccan women treated for breast carcinoma, the DNA extracted was treated by bisulphite and the targeted BRCA1/2 Amplicons were amplified by specific methylation primers (MSP). Results: the result shows that 62% of the samples were BRCA1 methylated in addition and negative result for BRCA2, these positive epigenetic factor were remarkable in women over 47 years and at the stage of malignant tumor.Conclusion: these results show that half of the methylated samples are positive and the majority are over 47 years old, and confirms the impact of age on methylation and might be other factor of breast cancer development.

DNA Methylation Is Correlated with Oxidative Stress in Myelodysplastic Syndrome—Relevance as Complementary Prognostic Biomarkers

Oxidative stress and abnormal DNA methylation have been implicated in cancer, including myelodysplastic syndromes (MDSs). This fact leads us to investigate whether oxidative stress is correlated with localized and global DNA methylations in the peripheral blood of MDS patients. Sixty-six MDS patients and 26 healthy individuals were analyzed. Several oxidative stress and macromolecule damage parameters were analyzed. Localized (gene promotor) and global DNA methylations (5-mC and 5-hmC levels; LINE-1 methylation) were assessed. MDS patients had lower levels of reduced glutathione and total antioxidant status (TAS) and higher levels of peroxides, nitric oxide, peroxides/TAS, and 8-hydroxy-2-deoxyguanosine compared with controls. These patients had higher 5-mC levels and lower 5-hmC/5-mC ratio and LINE-1 methylation and increased methylation frequency of at least one methylated gene. Peroxide levels and peroxide/TAS ratio were higher in patients with methylated genes than those without methylation and negatively correlated with LINE-1 methylation and positively with 5-mC levels. The 5-hmC/5-mC ratio was significantly associated with progression to acute leukemia and peroxide/TAS ratio with overall survival. This study points to a relationship between oxidative stress and DNA methylation, two common pathogenic mechanisms involved in MDS, and suggests the relevance of 5-hmC/5-mC and peroxide/TAS ratios as complementary prognostic biomarkers.

USAGE OF TRANSCRIPTIONAL REGULATOR LRP BASED BIOSENSOR FOR RESEARCH OF VALINE BIOSYNTHESIS PATHWAYS IN CORYNEBACTERIUM GLUTAMICUM CELLS

The biosensor construction based on Lrp gene was obtained, what contains a fluorescence protein gene under control of BrnFE gene promotor. It was displayed that the fluorescence of Corynebacterium glutamicum cells carrying the biosensor correlates with the production of valine, and with its help it is possible to study the biosynthesis of valine.

Molecular Dynamics Simulations Predict that rSNP Located in the HNF-1α Gene Promotor Region Linked with MODY3 and Hepatocellular Carcinoma Promotes Stronger Binding of the HNF-4α Transcription Factor

Our study aims to investigate the impact of the Maturity-onset diabetes of the young 3 disease-linked rSNP rs35126805 located in the HNF-1α gene promotor on the binding of the transcription factor HNF-4α and consequently on the regulation of HNF-1α gene expression. Our focus is to calculate the change in the binding affinity of the transcription factor HNF-4α to the DNA, caused by the regulatory single nucleotide polymorphism (rSNP) through molecular dynamics simulations and thermodynamic analysis of acquired results. Both root-mean-square difference (RMSD) and the relative binding free energy ΔΔGbind reveal that the HNF-4α binds slightly more strongly to the DNA containing the mutation (rSNP) making the complex more stable/rigid, and thereby influencing the expression of the HNF-1α gene. The resulting disruption of the HNF-4α/HNF-1α pathway is also linked to hepatocellular carcinoma metastasis and enhanced apoptosis in pancreatic cancer cells. To the best of our knowledge, this represents the first study where thermodynamic analysis of the results obtained from molecular dynamics simulations is performed to uncover the influence of rSNP on the protein binding to DNA. Therefore, our approach can be generally applied for studying the impact of regulatory single nucleotide polymorphisms on the binding of transcription factors to the DNA.

CISGENIC BIOLISTIC TRANSFORMATION FOR OBTAINING NEW FORMS OF POTATOES WITH IMPROVED RESISTANCE TO LATE BLIGHT

This article presents the results of application of cisgenic biolistic transformation for the accelerated production of new forms of potato with increased resistance to late blight. The reason for late blight development is the parasitic organism Phytophthora infestans, belonging to oomycetes (pseudo-fungi), which infects valuable agricultural plants. In this study, with the aim of combating P. infestans, a number of experiments on the biolistic transformation of the most common potato varieties Aksor and Nevskiy were carried out in Kazakhstan. Two potato genes – Rpi-vnt1.1 and StREM1.3 – were selected as targets for introduction. Expression of the first gene should be activated, and the expression of the REMORIN1.3 gene should be suppressed. Rpi-vnt1.1 was under the control of Solanum tuberosum polyubiquitin gene promotor (Pat) and Arabidopsis thaliana polyubiquitin 5 gene terminator (ubq5). Knock-down double stranded RNA-hairpin gene construction for StREM1.3 silencing was under the control of Solanum tuberosum phytochrome B gene promotor (phyB) and Arabidopsis thaliana hot-shock protein 18.2 terminator (HSP18.2). Three series of biolistic transformation were carried out, as a result of which 636 regenerated plants of potato varieties Aksor and Nevskiy were obtained. DNA was extracted from the plant material of potato transformant plants in the quality and quantity suitable for PCR analysis for the presence of an insert. PCR analysis was carried out, revealing 52 plants carrying the VNT insert. StREM1.3 silencing gene construction was detected in plant lines by qPCR, based on comparative analysis of of gene expression level and revealed 6 lines with reliably lower StREM1.3 expression level in comparison with wild-type plants.

A pH-dependent bolt involving cytosine bases located in the lateral loops of antiparallel G-quadruplex structures within the SMARCA4 gene promotor

Some lung and ovarian tumors are connected to the loss of expression of SMARCA4 gene. In its promoter region, a 44-nucleotides long guanine sequence prone to form G-quadruplex structures has been studied by means of spectroscopic techniques (circular dichroism, molecular absorption and nuclear magnetic resonance), size exclusion chromatography and multivariate analysis. The results have shown that the central 21-nucleotides long sequence comprising four guanine tracts of disparate length is able to fold into a pH-dependent ensemble of G-quadruplex structures. Based on acid-base titrations and melting experiments of wild and mutated sequences, the formation of a C·C+ base pair between cytosine bases present at the two lateral loops is shown to promote a reduction in conformational heterogeneity, as well as an increase in thermal stability. The formation of this base pair is characterized by a pKa value of 7.1 ± 0.2 at 20 °C and 150 mM KCl. This value, higher than those usually found in i-motif structures, is related to the additional stability provided by guanine tetrads in the G-quadruplex. To our knowledge, this is the first thermodynamic description of this base pair in loops of antiparallel G-quadruplex structures.