Biology subjects

Dranenko, N. O.

Publications and source records attributed to Dranenko, N. O..

3 recordsLinked to original sources

bioRxiv2023

Genome rearrangements drive evolution of ANK genes in Wolbachia

IntroductionGenus Wolbachia comprises endosymbionts infecting many arthropods and nematodes; it is a model for studying symbiosis as its members feature numerous, diverse mutualistic and parasitic adaptations to different hosts. In contrast to nematode-infecting Wolbachia, genomes of arthropod-infecting strains contain a high fraction of repetitive elements creating possibilities for multiple recombination events and causing genome rearrangements. The mechanisms and role of these features are still not fully understood. ResultsTransposons cover up to 18% of an arthropod-infecting Wolbachia genome and drive numerous genome rearrangements including inversions and segmental amplifications. ANK (ankyrin-repeat domain family) genes are also often found at the breakpoints of rearrangements, while less than 7% of them were found within locally collinear blocks (LCBs). We observed a strong correlation between the number of ANK genes and the genome size as well as significant overrepresentation of transposons adjacent to these genes. We also revealed numerous cases of integration of transposases to the ANK genes affecting the sequences and putative products of the latter. Our results uncover the role of mobile elements in the amplification and diversification of ANK genes. ConclusionsEvolution of arthropod-infecting Wolbachia was accompanied by diverse genome rearrangements driving the evolution of ANK genes important for bacteria-host interactions. This study demonstrates the effectiveness of our LCB-based approach to the Wolbachia genomics and provides a framework for understanding the impact of genome rearrangements on their rapid host adaptation.

evolutionary biology↗

bioRxiv2023

Evolutionary trajectories of secondary replicons in multipartite genomes

Most bacterial genomes have a single chromosome that may be supplemented by smaller, dispensable plasmids. However, approximately 10% of bacteria with completely sequenced genomes, mostly pathogens and plant symbionts, have more than one stable large replicon. Some secondary replicons are species-specific, carrying pathogenicity or symbiotic factors. Other replicons are common on at least the genus level, carry house-keeping genes, and may have a size of several million base pairs. We analyzed the abundance and sizes of large secondary replicons in different groups of bacteria and identified two patterns in the evolution of multipartite genomes. In nine genera of four families, Pseudoalteromonadaceae, Burkholderiaceae, Vibrionaceae, and Brucellaceae, we observed a positive correlation between the sizes of the chromosome and the secondary replicon with the slope in the range of 0.6-1.2. This indicates that in these genera the replicons evolve in a coordinated manner, with comparable rates of gene gain/loss, hence supporting classification of such secondary replicons as chromids. The second, more common pattern, features gene gains and losses mainly occurring in the primary replicon, yielding a stable size of the secondary replicon. Such secondary replicons are usually present in only a low fraction of the genus species. Hence, such replicons behave as megaplasmids. A mixed situation was observed in symbiotic genera from the Rhizobiaceae family where the large secondary replicons are of stable size, but present in all species. These results may provide a general framework for understanding the evolution of genome complexity in prokaryotes. SignificanceLarge secondary replicons are observed in representatives of many taxonomic groups of bacteria. Traditionally, they are referred to as second chromosomes, chromids, or megaplasmids, with little consistency, in particular because their evolution remains understudied. Here we demonstrate that the sizes of secondary replicons follow two main evolutionary trends: replicons whose size scales linearly with the size of the main chromosome (the suggested term chromids) typically contain numerous essential genes (rRNA, tRNA, ribosomal proteins), while large secondary replicons of stable size (termed megaplasmids) contain fewer or none such genes.

genomics↗

bioRxiv2021

Chromosome-encoded IpaH ubiquitin ligases indicate non-human pathogenic Escherichia

Until recently, Shigella and enteroinvasive Escherichia coli were thought to be primate-restricted pathogens. The base of their pathogenicity is the type 3 secretion system (T3SS) encoded by the pINV virulence plasmid, which facilitates host cell invasion and subsequent proliferation. A large family of T3SS effectors, E3 ubiquitin-ligases encoded by the ipaH genes, have a key role in the Shigella pathogenicity through the modulation of cellular ubiquitination that degrades host proteins. However, recent genomic studies identified ipaH genes in the genomes of Escherichia marmotae, a potential marmot pathogen, and an E. coli extracted from fecal samples of bovine calves, suggesting that non-human hosts may also be infected by these strains, potentially pathogenic to humans. We performed a comparative genomic study of the functional repertoires in the ipaH gene family in Shigella and enteroinvasive Escherichia from human and predicted non-human hosts. We found that fewer than half of Shigella genomes had a complete set of ipaH genes, with frequent gene losses and duplications that were not consistent with the species tree and nomenclature. Non-human host IpaH proteins had a diverse set of substrate-binding domains and, in contrast to the Shigella proteins, two different types of the NEL C-terminal domain. Only the ipaH9.8 gene was found in Escherichia derived from both human and non-human hosts. These results provide a framework for understanding of ipaH-mediated host-pathogens interactions and suggest a need for a genomic study of fecal samples from diseased animals.

microbiology↗