@article{FofanovProkopovKuhletal.2020,
  author    = {Fofanov, Mikhail V. and Prokopov, Dmitry Yu. and Kuhl, Heiner and Schartl, Manfred and Trifonov, Vladimir A.},
  title     = {Evolution of microRNA biogenesis genes in the sterlet (Acipenser ruthenus) and other polyploid vertebrates},
  series = {International Journal of Molecular Sciences},
  volume    = {21},
  journal   = {International Journal of Molecular Sciences},
  number    = {24},
  issn      = {1422-0067},
  doi       = {10.3390/ijms21249562},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-285230},
  year      = {2020},
  abstract  = {MicroRNAs play a crucial role in eukaryotic gene regulation. For a long time, only little was known about microRNA-based gene regulatory mechanisms in polyploid animal genomes due to difficulties of polyploid genome assembly. However, in recent years, several polyploid genomes of fish, amphibian, and even invertebrate species have been sequenced and assembled. Here we investigated several key microRNA-associated genes in the recently sequenced sterlet (Acipenser ruthenus) genome, whose lineage has undergone a whole genome duplication around 180 MYA. We show that two paralogs of drosha, dgcr8, xpo1, and xpo5 as well as most ago genes have been retained after the acipenserid-specific whole genome duplication, while ago1 and ago3 genes have lost one paralog. While most diploid vertebrates possess only a single copy of dicer1, we strikingly found four paralogs of this gene in the sterlet genome, derived from a tandem segmental duplication that occurred prior to the last whole genome duplication. ago1,3,4 and exportins1,5 look to be prone to additional segment duplications producing up to four-five paralog copies in ray-finned fishes. We demonstrate for the first time exon microsatellite amplification in the acipenserid drosha2 gene, resulting in a highly variable protein product, which may indicate sub- or neofunctionalization. Paralogous copies of most microRNA metabolism genes exhibit different expression profiles in various tissues and remain functional despite the rediploidization process. Subfunctionalization of microRNA processing gene paralogs may be beneficial for different pathways of microRNA metabolism. Genetic variability of microRNA processing genes may represent a substrate for natural selection, and, by increasing genetic plasticity, could facilitate adaptations to changing environments.},
  language  = {en}
}
@article{HoehneProkopovKuhletal.2021,
  author    = {H{\"o}hne, Christin and Prokopov, Dmitry and Kuhl, Heiner and Du, Kang and Klopp, Christophe and Wuertz, Sven and Trifonov, Vladimir and St{\"o}ck, Matthias},
  title     = {The immune system of sturgeons and paddlefish (Acipenseriformes): a review with new data from a chromosome-scale sturgeon genome},
  series = {Reviews in Aquaculture},
  volume    = {13},
  journal   = {Reviews in Aquaculture},
  number    = {3},
  doi       = {10.1111/raq.12542},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239865},
  pages     = {1709 -- 1729},
  year      = {2021},
  abstract  = {Sturgeon immunity is relevant for basic evolutionary and applied research, including caviar- and meat-producing aquaculture, protection of wild sturgeons and their re-introduction through conservation aquaculture. Starting from a comprehensive overview of immune organs, we discuss pathways of innate and adaptive immune systems in a vertebrate phylogenetic and genomic context. The thymus as a key organ of adaptive immunity in sturgeons requires future molecular studies. Likewise, data on immune functions of sturgeon-specific pericardial and meningeal tissues are largely missing. Integrating immunological and endocrine functions, the sturgeon head kidney resembles that of teleosts. Recently identified pattern recognition receptors in sturgeon require research on downstream regulation. We review first acipenseriform data on Toll-like receptors (TLRs), type I transmembrane glycoproteins expressed in membranes and endosomes, initiating inflammation and host defence by molecular pattern-induced activation. Retinoic acid-inducible gene-I-like (RIG-like) receptors of sturgeons present RNA and key sensors of virus infections in most cell types. Sturgeons and teleosts share major components of the adaptive immune system, including B cells, immunoglobulins, major histocompatibility complex and the adaptive cellular response by T cells. The ontogeny of the sturgeon innate and onset of adaptive immune genes in different organs remain understudied. In a genomics perspective, our new data on 100 key immune genes exemplify a multitude of evolutionary trajectories after the sturgeon-specific genome duplication, where some single-copy genes contrast with many duplications, allowing tissue specialization, sub-functionalization or both. Our preliminary conclusion should be tested by future evolutionary bioinformatics, involving all >1000 immunity genes. This knowledge update about the acipenseriform immune system identifies several important research gaps and presents a basis for future applications.},
  language  = {en}
}