Biology subjects

Drobysheva, A. V.

Publications and source records attributed to Drobysheva, A. V..

3 recordsLinked to original sources

bioRxiv2025

Mycoplasma gallisepticum FtsZ demonstrates properties that distinguish it from other known homologs

In bacteria, cell division usually occurs through binary fission, with the participation of genes from the dcw cluster. In mollicutes, this cluster is significantly reduced -- often only the ftsZ, ftsA, mraZ, and mraW genes remain, and sometimes ftsZ is completely absent. FtsZ is a key division protein that forms the Z-ring, but its role in mollicutes is questionable due to the absence of many cell division proteins and the cell wall. In the current study, we investigated the FtsZ protein of Mycoplasma gallisepticum, a bacterium with a reduced set of putative cell division genes (ftsZ, ftsA, ftsK). The results show that, unlike in well-studied bacteria, FtsZ in M. gallisepticum often exhibits polar rather than mid-cell localization. Overexpression of fluorescently labeled FtsZ enhances this polar localization and may lead to minicell formation. The FtsZ concentration was measured and, together with in vitro data, confirmed its ability to polymerize, similar to its homologs. Protein-protein interactions were also analyzed and confirmed the link of FtsZ to cell division. Overall, the results support the role of FtsZ in cell division, though its properties differ significantly from other known homologs.

molecular biology↗

bioRxiv2021

Template strand deoxyuridine promoter recognition by a viral RNA polymerase

Bacillus subtilis bacteriophage AR9 employs two strategies for efficient host takeover control and host antiviral defense evasion - it encodes two unique DNA-dependent RNA polymerases (RNAPs) that function at different stages of virus morphogenesis in the cell, and its double stranded (ds) DNA genome contains uracils instead of thymines throughout1,2. Unlike any known RNAP, the AR9 non-virion RNAP (nvRNAP), which transcribes late phage genes, recognizes promoters in the template strand of dsDNA and efficiently differentiates obligatory uracils from thymines in its promoters3. Here, using structural data obtained by cryo-electron microscopy and X-ray crystallography on the AR9 nvRNAP core, holoenzyme, and a promoter complex, and a variety of in vitro transcription assays, we elucidate a unique mode of uracil-specific, template strand-dependent promoter recognition. It is achieved by a tripartite interaction between the promoter specificity subunit, the core enzyme, and DNA adopting a unique conformation. We also show that interaction with the non-template strand plays a critical role in the process of AR9 nvRNAP promoter recognition in dsDNA, and that the AR9 nvRNAP core and a part of its promoter specificity subunit that interacts with the core are structurally similar to their bacterial RNAP counterparts. Our work demonstrates the extent to which viruses can evolve new functional mechanisms to control acquired multisubunit cellular enzymes and make these enzymes serve their needs.

molecular biology↗

bioRxiv2020

Structure and function of virion RNA polymerase of crAss-like phage

CrAss-like phages are a recently described family-level group of viruses that includes the most abundant virus in the human gut1,2. Genomes of all crAss-like phages encode a large virion-packaged protein2,3 that contains a DFDxD sequence motif, which forms the catalytic site in cellular multisubunit RNA polymerases (RNAPs)4. Using Cellulophaga baltica crAss-like phage phi14:2 as a model system, we show that this protein is a novel DNA-dependent RNAP that is translocated into the host cell along with the phage DNA and transcribes early phage genes. We determined the crystal structure of this 2,180-residue enzyme in a self-inhibited, likely pre-virion-packaged state. This conformation is attained with the help of a Cleft-blocking domain that interacts with the active site motif and occupies the RNA-DNA hybrid binding grove. Structurally, phi14:2 RNAP is most similar to eukaryotic RNAPs involved in RNA interference5,6, although most of phi14:2 RNAP structure (nearly 1,600 residues) maps to a new region of protein folding space. Considering the structural similarity, we propose that eukaryal RNA interference polymerases take their origin in a phage, which parallels the emergence of the mitochondrial transcription apparatus7.

molecular biology↗