PCID2, a subunit of the Drosophila TREX-2 nuclear export complex, is essential for both mRNA nuclear export and its subsequent cytoplasmic trafficking.

The TREX-2 complex is essential for the general nuclear mRNA export in eukaryotes. TREX-2 interacts with the nuclear pore and transcriptional apparatus and links transcription to the mRNA export. However, it remains poorly understood how the TREX-2-dependent nuclear export is connected to the subsequent stages of mRNA trafficking. Here, we show that the PCID2 subunit of Drosophila TREX-2 is present in the cytoplasm of the cell. The cytoplasmic PCID2 directly interacts with the NudC protein and this interaction maintains its stability in the cytoplasm. Moreover, PCID2 is associated with the cytoplasmic mRNA and microtubules. The PCID2 knockdown blocks nuclear export of mRNA and also affects the general mRNA transport into the cytoplasm. These data suggest that PCID2 could be the link between the nuclear TREX-2-dependent export and the subsequent cytoplasmic trafficking of mRNA.

[The SAGA Deubiquitinilation (DUB) Module Participates in Pol III-Dependent Transcription].

SAGA, the multicomponent complex responsible for acetylation of histone N-terminal lysine residues, is involved in the transcription activation of a wide range of eukaryote genes. SAGA contains a protein module, DUB, which is responsible for histone deubiquitination. In this paper we show that the DUB module may be found within cells independently of SAGA. In the absence of" SAGA, the DUB module may be recruited to the promoters of Pol III-transcribed genes, but not to the Pol II-dependent promoters. The DUB module is required to recruit transcription factor Brfl, a subunit of the Pol III-recruiting TFIIIB complex, to the promoters of Pol III-dependent genes. The DUB-module interacts with Pol III in vivo. The DUB-module is essential for recruiting both TFIIIB complexes and PBP complexes to the promoters of Pol III-dependent genes.

[Glycol and Phosphate Depot Forms of 4- and/or 5-Modified Nucleosides Exhibiting Antibacterial Activity].

Resistance developed to the majority of drugs used to treat infectious diseases warrants the design of new compounds effective against drug-resistant strains of pathogens. Recently, several groups of modified nucleosides have been synthesized and showed significant antibacterial activity in vitro, but their further studies were difficult to undertake because of their low solubility in aqueous solutions. Nevertheless, new compounds, well soluble in water-organic solutions, were synthesized and found to be more effective in inhibiting the growth of Gram-positive bacteria and mycobacteria. The water-soluble forms of modified nucleosides under study were assumed to be their depot forms. To check the assumption, the compounds were tested for hydrolysis in various media and their molecular docking was performed into the active center of the putative target, Mycobacterium tuberculosis flavin-dependent thymidylate synthase ThyX. Computer modelling showed that the water-soluble analogs do not act as ThyX inhibitors, supporting the assumption of their depot nature. The compounds were resistant to chemical hydrolysis but were hydrolyzed when incubated with porcine liver carboxylesterase, human serum, or Staphylococcus aureus 209P. The results demonstrate that the compounds are most likely depot forms of modified nucleosides.

[Interactions of the TREX-2 complex with mRNP particle of ß-tubulin 56D gene].

mRNA transport from the nucleus to the cytoplasm is an essential step of eukaryotic gene expression. A pre-mRNA molecule undergoes modification, such as 5'-capping, splicing, and 3'-end processing, in the nucleus. The molecule being modified interacts with a large number of proteins and, thus, mRNP particles are formed. The binding of factors involved in nuclear export also occurs during transcription and mRNA processing. We have shown that the functioning of TREX-2, an mRNA export complex, is restricted to the nucleus. We used the method of RNA coprecipitation that enables the selective extraction of RNA-protein complexes from samples to show that the transcription elongation complex TREX interacts with mRNA of the ß-tubulin 56D gene over the entire length of the molecule. The capping protein Cbp80 reacted both with the cap structure and with a specific part of the coding mRNA of the ß-tubulin 56D gene. The TREX-2 complex that mediates mRNA export from the nucleus to the cytoplasm is bound to the same part of the coding sequence. Thus, we identified a common binding site for all of the complexes under investigation on the mRNA of ß-tubulin 56D. Co-immunoprecipitation reactions performed with S2 cell extracts revealed interactions between the components of complexes involved in transcription elongation, maturation, and export of mRNA. The model of molecular folding for the mRNP particle involving the mRNA of ß-tubulin 56D has been proposed.

Antibiotic Activity of Probiotic Strain Bacillus subtilis 534 Against Clinical Isolates of Acinetobacter baumannii.

Probiotic strain Bacillus subtilis 534 is the base of sporobacterin, a pharmaceutical. In submerged culture it showed antibiotic activity against many of gram-positive and gram-negative bacteria and fungi. The spectrum of the antimicrobial activity of the culture fluid depended on the.cultivation time and aeration intensity. It was shown that component No. 1 of the antibiotic complex was effective against clinical isolates of Acinetobacter baumannii: 20 out of 24 isolates were susceptible to component No. 1, including 15 strains out of 16 panresistant isolates.

Complete Genome Sequences of Streptomyces albus Strain INA 01303.

Here, we report the complete genome sequence of Streptomyces albus strain INA 01303, which was isolated from the Salt Lake Tambukan (Russia). The genome consists of a linear 6,840,896-nucleotide chromosome. This strain is predicted to produce a range of novel secondary metabolites with antibiotic activity.