Springer Science and Business Media LLC

The important role of mitochondria in the process of programmed cell death is widely accepted now. There is a set of nuclear-encoded mitochondrial proteins involved in this process. Apart from this, a mitochondrion contains its own genetic apparatus comprising mtDNA and replication, transcription, and translation systems. However, a mechanism of mitochondria genetic information realization under apoptosis-inducing conditions has been understood poorly. Here, using real-time PCR technique, the number of mitochondrial genes and their transcripts in mouse spleen cells after whole-body X-ray irradiation at the dosage of 10 Gy has been evaluated. During 5 h after the irradiation, nuclear DNA was subjected to fragmentation, whereas mtDNA remained intact. Moreover, in the course of time after irradiation the number of mtDNA copies increased threefold. The process of mtDNA transcription was more susceptible to irradiation: 1 h after exposure the number of ND2, ND4, and CYTB gene transcripts sharply decreased. At 24 and 72 h after irradiation, ND2 and ND4 transcripts recovered to the control values, while CYTB remained rather low; no significant decrease of ATP6 transcripts was observed within the whole period of observation. The difference in mRNA levels of genes transcribed under the control of the same promoter for mice to be grown both under normal conditions and after X-ray irradiation allows us to propose that there is a posttranscriptional mechanism which regulates expression of mitochondrial genes and provides different recovery rates for different mitochondrial transcripts during the development of apoptosis.

In spite of decades of research, our understanding of the principles of antibiotic binding to the ribosome and the mechanisms of drug action remains only fragmentary. Recent progress in biochemical and genetic studies of some “old” and new antibiotics and the availability of high-resolution structures of the ribosome subunits allows mapping the antibiotic-binding sites at atomic resolution. In this review, interaction of three groups of antibiotics with the ribosome and the mechanisms of the drug action are discussed, considering the data used to map the binding sites of the new macrolide derivatives, ketolides, a novel clinically important antibiotic linezolid, and a still experimental drug evernimicin.

A method for fluorescently labeled single-stranded DNA (ssDNA) production during single-stage polymerase chain reaction (PCR) for subsequent hybridization on a biochip was described. This approach, whose efficiency was confirmed in the case of DARC gene, is considered as an alternative to two-stage nested PCR, consisting of two separate reactions: symmetric and asymmetric. Implementation of PCR in a single stage was achieved due to the use of a truncated excess primer in the second stage that does not anneal on the matrix during the cycles of symmetric stage of PCR and that enters the reaction after decrease of the annealing temperature in asymmetric stage. As a result, high efficiency of genotyping by means of hybridization on biochips is maintained. The suggested approach will allow us to reduce the time, working hours, and risk of contamination when researching biochips.

A method was elaborated to construct combined artificial immunogens simulating virus particles. The gist was exposing protein antigenic determinants of one virus on the particle surface and delivering plasmids with genes for antigenic proteins of another virus to specialized immune cells. Such immunogens were constructed and shown to induce biosynthesis of specific antibodies against HIV-1 and the tick-borne encephalitis virus. The level and duration of the humoral and cell responses were assayed.

In this minireview I briefly describe the new methods suggested for cloning sequences identical by descent, homo-or hemizygously deleted, amplified or polymorphic, and compare them with the most efficient techniques developed earlier. The new methods include cloning of identical sequences (CIS), cloning of polymorphic sequences (COP), and cloning of deleted sequences (CODE). Although these methods are based on the same combination of biochemical techniques, their aims are different. These methods are fully complementary, and they may be combined to analyze a given object. If one aims to clone a disease gene responsible for familial cancer syndrome, these methods may be applied as follows. CIS can be used to identify the sequences identical by descent comparing the DNA obtained from affected or unaffected family members. COP can be used to find sequences that are different between affected and unaffected members, and CODE would be useful to compare tumor and normal (control) samples to isolate, deleted sequences (putative candidate tumor suppressor genes) and amplified sequences (putative oncogenes). The COP and CODE procedures can be applied to analyze the CpG islands, thus allowing direct candidate gene identification.

The oncolytic potential of the attenuated mumps virus (MV) vaccine strain Leningrad-3 (L-3) was evaluated in a panel of four human metastatic melanoma cell lines. The lines were shown to be susceptible and permissive to MV infection. Efficient MV replication led to death of melanoma cells, but the effect differed among the cell lines. Possible mechanisms mediating the selectivity of MV L-3 towards the cell lines were explored. Replicative and oncolytic activity of MV was found to depend on the expression pattern of type I interferon genes. None of the melanoma cell lines showed induction of expression of the total spectrum of genes required to inhibit virus replication. Based on the results, MV L-3 was assumed to be a promising oncolytic agent for human melanoma cells.

Abstract—The importance of root nodule bacteria in biotechnology is determined by their distinctive feature: symbiotic nitrogen fixation resulting in the production of organic nitrogen-containing compounds. While interacting with host legume plants, the cells of these bacteria undergo global changes at all levels of expression of genetic information leading to the formation in root nodules of so-called bacteroids functioning as nitrogen fixation factories. The molecular mechanisms underlying plant-microbial symbiosis are actively investigated, and one of the most interesting and poorly studied aspects of this problem is the species-specificity of interaction between root nodule bacteria and host plants. In this work we have performed the proteomic analysis of the Sinorhizobium meliloti bacteroids isolated from two legume species: alfalfa (Medicago sativa L.) and yellow sweet clover (Melilotus officinalis L.). It has been shown that the S. meliloti bacteroids produce a lot of proteins (many of them associated with symbiosis) in a host-specific manner, i.e., only in certain host plant species. It has been demonstrated for the first time that the levels of expression in bacteroids of the genes encoding the ExoZ and MscL proteins responsible for the synthesis of surface lipopolysaccharides and formation of a large conductance mechanosensitive channel, respectively, depend on a host plant species that confirms the results of proteomic analysis. Overall, our data show that the regulation of bacteroid development by the host plant has species-specific features.

The assembly of LIM-homeodomain (LIM-HD) transcriptional complex plays important roles in early neuronal development. The stability of LIM-HD is controlled by single-strand binding protein 3 (SSBP3) via a cascade mechanism protecting it from proteasomal degradation. The expression level of SSBP3 has to be precisely regulated. Although a decrease of SSBP3 level is associated with several diseases, the mechanism of SSBP3 downregulation and whether SSBP3 itself is subject to proteasomal degradation remain largely unknown. Two strongly conserved transcripts of the SSBP3 gene, SSBP3a and SSBP3c, were cloned from a human brain cDNA library. By RT-PCR, we show that Ssbp3c is continuously expressed in both embryonic and adult mouse brain, whereas Ssbp3a is restricted to embryonic brain tissue. By co-IP and GST pulldown assays, we identified SIVA1 as a novel SSBP3-binding factor. In a ubiquitination assay, we show that SIVA1 enhances the ubiquitination of SSBP3 and regulates its abundance. Our findings reveal the proteasomal degradation of SSBP3 for the first time and provide a rationale for an SIVA1-SSBP3-dependent mechanism for the disassembly of LIM-HD multiprotein complexes.