Doklady Biochemistry and Biophysics最新文献

6-azido-2-chloropurine-2′-deoxyriboside, a valuable precursor for the preparation of modified 2-chloropurine nucleosides substituted at the 6-position of the heterocyclic base, was obtained by enzymatic transglycosylation. 6-azido-2-chloropurine-2′-deoxyriboside can also be used as a photocross-linking agent to study the nucleic acids—proteins interactions. A type II nucleoside deoxyribosyltransferase from Lactobacillus leichmannii was used as a biocatalyst. The optimal conditions for the formation of 6-azido-2-chloropurine-2′-deoxyriboside using 7-methyl-2′-deoxyguanosine as a carbohydrate residue donor were determined.

In this study, promoter sequences predicted by the MAHDS method in the Oryza sativa genome were analyzed using three genome annotations: RefSeq NCBI, Rice Genome Annotation Project, and Ensembl. Part of the predicted promoters was found to be located near annotated genes, which indicates their potential functional role. The remaining sequences, considered as potentially novel regulatory elements, were examined using YAPP for the presence of core promoter motifs and their functional combinations. All analyzed predicted promoters contain either an Inr or a TATA motif—the key elements involved in transcription initiation. The identified motif combinations suggest a high likelihood of transcriptional activity in these sequences, and the consistency of the results with annotated data and CAGE-seq signals supports the reliability and applicability of the MAHDS method.

The functioning of proteins in a cell cannot be studied without analyzing their content in the cell. The most commonly used method of analysis, Western blotting, cannot always be used due to the impossibility of obtaining antibodies that specifically recognize the protein of interest. At the same time, Western blotting is a semi-quantitative method of analysis and does not allow determining the exact content of protein in the cell. In this work, we used the protein complementation method for the qualitative and quantitative assessment of the hTERP protein content in the cell. Using genome editing, a HiBiT epitope was introduced to the C-terminus of the hTERP protein, the complementation of which with LgBiT restores active luciferase. As a result, we determined the hTERP protein content in the HEK293T cell line.

Ferroptosis, an iron-dependent form of regulated cell death, represents an emerging therapeutic vulnerability in colorectal cancer (CRC). However, the epigenetic mechanisms controlling ferroptosis sensitivity in CRC remain poorly understood. Here, we identify histone deacetylase 3 (HDAC3) as a pivotal epigenetic suppressor of ferroptosis. Both pharmacological inhibition and genetic knockdown of HDAC3 significantly enhanced ferroptosis sensitivity, as evidenced by elevated intracellular ferrous iron (Fe²⁺) and lipid peroxidation. Mechanistically, inhibition of HDAC3 reduced the expression of nuclear factor erythroid 2–related factor 2 (NRF2), a master antioxidant transcription factor, thereby leading to downregulation of glutathione peroxidase 4 (GPX4), a central ferroptosis defense gene. Notably, NRF2 knockdown abolished GPX4 downregulation by HDAC3 inhibition, whereas GPX4 overexpression rescued the ferroptotic phenotype caused by HDAC3 depletion. Collectively, these findings define an HDAC3–NRF2–GPX4 axis that suppresses ferroptosis in CRC, and highlight HDAC3 as a potential therapeutic target for ferroptosis-based cancer treatment.

The expression profile of key genes regulating flowering initiation (ID1, DLF1, ZCN6, ZCN7, and ZCN8) of Zea mays L. was determined in the leaf axils of the reproductive and adjacent nodes during the flowering initiation. The similarity of the inter-node dynamics of the ID1, DLF1, ZCN7, and ZCN8 gene expression was shown throughout the entire measurement period. It was determined that ~10 days before visual detection of the inflorescence meristem, the expression of the flowering activator genes ID1, DLF1, ZCN7, and ZCN8 significantly increased in the reproductive node compared to the adjacent nodes, while the flowering inhibitor gene ZCN6 expression decreased to trace values at all nodes.

A comparison of the incidence of myocardial infarction during the day was performed with the diurnal distribution of spikes in TiNi detector readings. Based on long-term monitoring data, it was shown that the maximum number of spikes on the TiNi detector graphs is observed between 7 and 10 a.m. local time. It is known that a similar diurnal pattern occurs in the case of cardiovascular complications. Based on the analysis of synchronism effects previously discovered using the TiNi detector, the properties of the factor acting on the detector, capable of influencing both the behavior of the TiNi system and the state of living organisms, were determined. This approach allows us to obtain new data on the mechanisms of the impact of external factors on the state of the biosphere.

Basic fibroblast growth factor (bFGF) is a potent mitogen implicated in tumor progression, yet its precise role in cancer cell invasion remains multifaceted. Here, we unveiled a dose-dependent, biphasic regulatory effect of bFGF blockade on the invasiveness of lung cancer cells. Using a neutralizing monoclonal antibody against bFGF (bFGF Ab), we demonstrated that moderate neutralization of bFGF inhibited tumor cell invasion. Conversely, excessive bFGF blockade paradoxically enhanced the invasive capacity of lung cancer cells. Furthermore, we showed that the divergent invasive phenotypes arising from varying degrees of bFGF inhibition were mediated by altered vascular endothelial growth factor (VEGF) secretion. These findings underscore the critical importance of dose optimization in bFGF-targeted therapies, particularly concerning their impact on lung cancer invasiveness, and identify VEGF as a key mediator of these effects.

The regularities of tumor induction and growth were studied in mice after a single ex vivo irradiation with a helium ion beam of Ehrlich adenocarcinoma ascites cells (EAC) at doses of 10 and 20 Gy in two positions of the Bragg curve (before the peak and at the peak) in comparison with X-ray radiation at the same doses. It was shown that the frequency of induction and delay in tumor appearance depend on the dose of helium ion irradiation. The following parameters were determined: the time of a fivefold increase in the EAC volume, tumor growth inhibition, tumor growth index (TGI), and lifetime increase (LTI) in mice. A decrease in the TGI values and an increase in the LTI values occurred with increasing dose for all types of radiation. The relative biological effectiveness (RBE) value for helium ions determined by the area under the EAC growth dynamics curves reached a maximum value of 1.8 upon irradiation at the Bragg peak at a dose of 20 Gy.

Bioinformatic methods have been used to predict a new subclass of proteins among plant phosphotransmitters involved in the signaling system of multistep phosphorelay. In contrast to the canonical soluble nucleocytosolic forms, the found noncanonical phosphotransmitter sequences, belonging to a wide range of plant taxa, potentially contain transmembrane domains. This suggests localization of such proteins on cell membranes and, therefore, a different function in signaling than that of canonical phosphotransmitters. We tested the functionality of the transmembrane domain of the phosphotransmitter using the protein of the tea plant Camellia sinensis. The membrane localization of the transiently expressed recombinant phosphotransmitter with this domain was confirmed by microscopy and immunoblotting. Thus, this is the first study to obtain experimental evidence for the existence of membrane-bound plant phosphotransmitters with as yet unknown functions. These data suggest the presence of a noncanonical membrane branch of signal transduction in the multistep phosphorelay system in plants.

To study the repertoire of the T-cell receptor in chronically exposed persons in the long-term period. The study involved 48 people who were divided into two groups: a group of exposed persons (31 individuals with the mean accumulated dose to red bone marrow (RBM) of 981 ± 130 mGy) and a comparison group (17 individuals, the mean accumulated dose to RBM of 25.3 ± 5.91 mGy). The study groups did not differ significantly in age, gender, and ethnicity. The repertoire of Vβ-segments of the T-cell receptor of the peripheral blood T-lymphocytes of exposed persons was analyzed by flow cytometry method. 24 Vβ-segments of the T-cell receptor were studied. Statistical processing of the obtained data was carried out using the Wilcoxon signed-rank test, and a direct description of Vβ-segment repertoire of the T-cell receptor was performed using the Lorenz curve and the Gini-TCR index. The study revealed a statistically significant increase in the number of Vβ3 and Vβ5.2 T-cell receptor segments in exposed individuals relative to the comparison group (p = 0.03 and p = 0.003, respectively). It was also shown that the distribution of the Vβ-segments of the T-cell receptor was uneven in both study groups. However, there was no significant difference between the repertoires of the T-cell receptor of the studied groups by the Gini-TCR index (p = 0.14).