Biology subjects

Pospelova, M.

Publications and source records attributed to Pospelova, M..

3 recordsLinked to original sources

bioRxiv2025

Bighorn sheep T2T genome assembly reveals differences in immune genes: a potential cause of high morbidity due to respiratory pathogens

The bighorn sheep (Ovis canadensis), despite its close relation to domestic sheep, suffer higher morbidity and mortality from respiratory disease complexes, likely due to genetic differences in immune responses. Unraveling highly repetitive regions such as immune loci and genetic differences was problematic until now. We generated a bighorn sheep telomere-to-telomere assembly, adding 14.28% of novel sequence compared to the previous reference. This enabled the first complete immune loci annotation revealing the IGL and TR loci are significantly short in bighorn sheep. Importantly, a critical immune gene GBP5 and ZNF501, involved in Golgi-mediated immune response, are lacking in bighorn but present in domestic sheep. Re-analysis of a Mycoplasma ovipneumoniae carriage study, using this assembly, identified the immune gene CAPN2 as a key genetic marker for disease carriage, not observable in the original study. This work provides a critical resource for identifying phenotype-linked genetic variation and exploring evolutionary adaptations of bighorn sheep.

genomics↗

bioRxiv2025

Comparative analysis of mammalian adaptive immune loci revealed spectacular divergence and common genetic patterns

Adaptive immune responses are mediated by the production of adaptive immune receptors, antibodies and T-cell receptors, that bind antigens, thus causing their neutralization. Unlike other proteins, adaptive immune receptors are not fully encoded in the germline genome and result from a complex of somatic processes collectively called V(D)J recombination affecting germline immunoglobulin (IG) and T-cell receptor (TR) loci consisting of template genes. While various existing studies report extreme diversity of antibodies and T-cell receptors, little is known about the diversity of germline IG and TR loci. To overcome this gap, the first comparative analysis of full-length sequences of IG/TR loci across 44 mammalian species from 13 taxonomic orders was performed. First, germline genes counts were shown to correlate in IGH/IGL and TRA/TRB and anticorrelate in IGK/IGL, possibly indicating co-evolution between corresponding chains. Second, structures of IG/TR loci were analyzed, and it was shown that IG/TR loci formed by long arrays of high multiplicity repeats are more common for species that have experienced population bottlenecks. Finally, haplotypes of IG/TR loci with little or no sequence similarity within a species were found, suggesting that they may have a limited potential for homologous recombination. These results demonstrate that IG/TR loci are rapidly evolving genomic regions whose structural variation is shaped by the population history of the species and open new perspectives for immunogenomics studies.

genomics↗

bioRxiv2022

Analyzing patterns in tyrosine sulfation in naive antibody repertoires

HIV-1 infects a subset of immune cells identified by the receptor CD4 and a coreceptor, CCR5 or CXCR4. Previous studies revealed bnAbs against HIV-1 with antigen-binding sites mimicking binding sites of CCR5. Such antibodies are characterized by post-translationally sulfated tyrosines and anionic motifs in long complementarity determining regions 3 (CDR3s) of the heavy chains. Despite the great therapeutic potential of human antibodies mimicking CCR5, their immunogenetic signatures remain unknown. In this study, we analyzed human naive heavy chain antibody repertoires and described the most common VDJ recombination scenarios generating CDR3s with sulfated tyrosines and anionic motifs. We showed ~77% of such CDR3s are generated using seven D genes from two families, IGHD3 and IGHD4. We also demonstrated that sulfated tyrosines and anionic motifs are a common feature of mammalian germline D genes.

immunology↗