Molecular Biology最新文献

Abstract—The study of molecular and genetic mechanisms of sex determination in the poplar is of interest not only in the fundamental science, but also in the applied research. In landscaping of large settlements, it is advisable to use male individuals of the Populus genus due to their hypoallergenicity and increased resistance to environmental pollution, stress conditions, and pathogens. However, sex determination in poplars is complicated by the complex genetic structure of the sex-determining region of the genome (SDR). In this review, the emergence, evolution, structure, and function of the SDR in the genus Populus are discussed. Current insights into the structure and function of the key regulator of sex selection in poplars, orthologue of the ARR16/ARR17 gene and the possible roles of other genes that are differentially expressed between male and female plants, including microRNAs, in this process are discussed in detail. The great diversity of species and the high complexity of SDR organization justify the need for further study of the molecular mechanisms of sex determination in poplars.

This study investigated the effect of knockout of six Hsp70 genes (orthologues of the mammalian genes Hspa1a, Hspa1b, Hspa2, and Hspa8) on age-related changes in gene expression in the legs of Drosophila melanogaster, which contain predominantly skeletal muscle bundles. For this, the leg transcriptomic profile was examined in males of the w¹¹¹⁸ control strain and the Hsp70^– strain on the 7th, 23rd and 47th days of life. In w¹¹¹⁸ flies, an age-related decrease in the locomotion (climbing) speed (a marker of functional state and endurance) was accompanied by a pronounced change in the transcriptomic profile of the leg skeletal muscles, which is conservative in nature. In Hsp70 ^– flies, the median lifespan was shorter and the locomotion speed was significantly lower compared to the control; at the same time, complex changes in the age-related dynamics of the skeletal muscle transcriptome were observed. Mass spectrometry-based quantitative proteomics showed that 47-day-old Hsp70 ^– flies, compared with w¹¹¹⁸ flies, demonstrated multidirectional changes in the contents of key enzymes of glucose metabolism and fat oxidation (glycolysis, pentose phosphate pathway, Krebs cycle, beta-oxidation, and oxidative phosphorylation). Such dysregulation may be associated with a compensatory increase in the expression of other genes encoding chaperones (small Hsp, Hsp40, 60, and 70), which regulate specific sets of target proteins. Taken together, our data show that knockout of six Hsp70 genes slightly reduced the median lifespan of flies, but significantly reduced the locomotion speed, which may be associated with complex changes in the transcriptome of the leg skeletal muscles and with multidirectional changes in the contents of key enzymes of energy metabolism.

Abstract

The complement inhibitor CD55/DAF is expressed on many cell types. Dysregulation of CD55 expression is associated with increased disease severity in influenza A infection and vascular complications in pathologies that involve excessive activation of the complement system. A luciferase reporter system was used to functionally analyze the single nucleotide polymorphism rs2564978 in the U937 human promonocytic cell line. The polymorphism is in the promoter of the CD55 gene, and its minor allele T is associated with a severe course of influenza A(H1N1)pdm09. A decreased activity of the CD55 promoter carrying the minor rs2564978(T) allele was observed in activated U937 cells, which provide a cell model of human macrophages. Using bioinformatics resources, PU.1 was identified as a potential transcription factor that may bind to the CD55 promoter at the rs2564978 site in an allele-specific manner. The involvement of PU.1 in modulating CD55 promoter activity was verified by a PU.1 genetic knockdown with small interfering RNAs under specific monocyte activation conditions.

Abstract—Type 2 diabetes is a complex and multifactorial metabolic disorder. The frequency of type 2 diabetes has dramatically increased worldwide. Long noncoding RNAs play a regulatory role in pathological processes of type 2 diabetes. The aim of the study was to analyze TP53TG1, LINC00342, MALAT1, H19, and MEG3 lncRNAs in patients with type 2 diabetes and metabolic parameters, as well as the risk of diabetic retinopathy. Participants included 51 patients with diabetes and 70 healthy individuals. The expression of the TP53TG1 and LINC00342 genes was significantly decreased in the patients with diabetes compared to healthy individuals. MALAT1 gene expression was higher in diabetes patients. H19 gene expression was increased in the patients with diabetic retinopathy compared patients without retinopathy. TP53TG1, LINC00342, and MEG3 expression was decreased in patients with diabetic retinopathy and MALAT1 expression was increased. H19 is positively correlated with triglyceride levels; TP53TG1 and LINC00342 are positively correlated with HbA1c levels and fasting glucose levels. MALAT1 is negatively correlated with HDL levels and positively correlated with LDL levels. A decrease in the expression level of TP53TG1 and LINC00342 and an increase in the level of MALAT1 in diabetes, as well as an association with glycemic control, indicate the role of the studied noncoding RNAs in the development of type 2 diabetes mellitus and retinopathy and can be considered as candidates for early diagnosis of type 2 diabetes.

Abstract—Titin is a multidomain protein of striated and smooth muscles of vertebrates. The protein consists of repeating immunoglobulin-like (Ig) and fibronectin-like (FnIII) domains, which are β-sandwiches with a predominant β-structure, and also contains disordered regions. In this work, the methods of atomic force microscopy (AFM), X-ray diffraction, and Fourier transform infrared spectroscopy were used to study the morphology and structure of aggregates of rabbit skeletal muscle titin obtained in two different solutions: 0.15 M glycine-KOH, pH 7.0 and 200 mM KCl, 10 mM imidazole, pH 7.0. According to AFM data, skeletal muscle titin formed amorphous aggregates of different morphologies in the above two solutions. Amorphous aggregates of titin formed in a solution containing glycine consisted of much larger particles than aggregates of this protein formed in a solution containing KCl. The “KCl-aggregates” according to AFM data had the form of a “sponge”-like structure, while amorphous “glycine-aggregates” of titin formed “branching” structures. Spectrofluorometry revealed the ability of “glycine-aggregates” of titin to bind to the dye thioflavin T (TT), and X-ray diffraction revealed the presence of one of the elements of the amyloid cross β-structure, a reflection of ~4.6 Å, in these aggregates. These data indicate that “glycine-aggregates” of titin are amyloid or amyloid-like. No similar structural features were found in “KCl-aggregates” of titin; they also did not show the ability to bind to thioflavin T, indicating the non-amyloid nature of these titin aggregates. Fourier transform infrared spectroscopy revealed differences in the secondary structure of the two types of titin aggregates. The data we obtained demonstrate the features of structural changes during the formation of intermolecular bonds between molecules of the giant titin protein during its aggregation. The data expand the understanding of the process of amyloid protein aggregation.

Abstract

Uveal melanoma (UM) is a neuroectodermal tumor that results from malignant transformation of melanocytes in the eye uvea, including the iris, the ciliary body, and the choroid. UM accounts for 5% of all melanoma cases and is extremely aggressive with half of the UM patients developing metastases within the first 1‒2 years after tumor development. Molecular mechanisms of UM carcinogenesis are poorly understood, but are known to differ from those of skin melanoma. Activating mutations of the GNAQ and GNA11 genes, which code for the large G protein subunits Gq and G11, respectively, are found in 90% of UM patients. The Gaq/PKC/MAPK signaling pathway is a main signaling cascade that leads to the transformation of melanocytes of the uveal tract, and major regulators of the cascade provide targets for the development of drugs. Metastatic UM (MUM) is most often associated with mutations of BAP1, EIF1AX, GNA11, GNAQ, and SF3B1. A combination of a commercial expression test panel of 15 genes and a mutation panel of 7 genes, supplemented with data on the size of the primary tumor, is highly efficient in predicting the risk of metastasis. The risk of metastasis determines the choice of therapy and the patient follow-up regimen. However, no systemic therapy for MUM has been developed to date. New drugs undergoing clinical trials are mostly targeted drugs designed to inhibit the protein products of mutant genes or immunotherapeutic agents designed to stimulate the immune response against specific antigens. In addition to these approaches, potential therapeutic targets of epigenetic regulation of UM development are considered in the review.

Abstract

The functions of actin and its motor proteins myosins in the cytoplasm have been the subject of research for more than 100 years, but the existence and function of these proteins in the nucleus has been a matter of debate until recently. Recent data has clarified the role of actin and myosin molecules in controlling the dynamics of processes in the cell nucleus, chromatin organization and genome integrity. New microscopy techniques and the use of modified actin-binding probes have made it possible for the first time to directly visualize the polymerization of actin filaments in the nucleus of living cells. Here we discuss the processes that control the dynamic balance of actin and myosins between the nucleus and the cytoplasm, as well as the role of these proteins in the regulation of transcription, DNA repair, chromatin reorganization, tumor transformation and cell differentiation.

Abstract

Long non-coding RNAs (lncRNAs) are involved in many cellular processes while displaying high tissue specificity. In contrast, protein-coding genes, including the category of housekeeping ones, exhibit broad expression patterns. The aim of this study was to highlight the functional importance of widely expressed lncRNAs. We analyzed experimental data from cell-growth screen of lncRNA loci in human cells, which allowed us to identify 18 lncRNA hits. Notably, these lncRNAs were not only widely expressed in most human tissues, but also played functional roles within them. Detail investigation revealed them encompass a variety of molecular functions, from cardiomyocyte damage controlling to macrophage class switching. Interestingly, experimental data highlighted the fact that a significant part of these lncRNAs encoded small but functional polypeptides. A set of lncRNAs, NEAT1, SNHG1, SNHG7, SNHG12, SNHG15, SNHG16, MIR17HG, LINC00680, LINC00263 and LINC00339, that were highly likely to be translated into small polypeptides was identified. Additionally, for EPB41L4A-AS1, CRNDE, SNHG6, LINC00493, and LINC01420, a dual function associated with both the RNA sequences and small proteins they encoded was established.

Abstract

The cadherin superfamily molecules, functioning as cell adhesion molecules, are recognized to play roles in both physiological and pathological processes. The cadherin-based adherent junction (CAJ) is believed to interact with presenilin-1 (PS-1), suggesting that disruptions in CAJ structures might contribute to neurodegeneration, potentially leading to Alzheimer’s Disease (AD). Yet, the specific expression patterns of cadherin superfamily mRNA remain somewhat ambiguous. This research utilized in situ hybridization (ISH) to examine the expression and localization of cadherin mRNA in AD mouse model brains. Long cRNA probes targeting cadherin revealed endogenous mRNA expression in brain sections. Interestingly, senile plaques in the AD mouse brain were also bound to these probes. This binding, however, did not exclusively denote cadherin mRNA, as ISH detected both antisense and sense cRNA probes. Our data suggest that although antisense cRNA probes effectively detected cadherin mRNA expression in AD brain cells, their association with senile plaques may not specifically indicate cadherin mRNA expression.