Researchers find repeated gene duplication and genetic diversification in protein kinase R in mouse-eared bats

TO) Sites undergoing positive selection in mammalian protein kinase R (PKR). The graphic panels represent the posterior probabilities of positive selection [Bayes empirical Bayes (BEB)] (axis y) in the M2 model (ω > 1) for each codon (axis x). Red bars indicate sites with BEB >0.95. The numbers in parentheses are the total species analyzed. Viral antagonists: US11 herpes virus, NS1A influenza A virus (IAV), poxvirus E3 and K3 (green striped boxes), NS5A hepatitis C virus (HCV), and human immunodeficiency virus Tat, reported to interact directly with PKR. (b) Maximum likelihood phylogeny of bat PKR indicating branches undergoing positive selection (P < 0.05, in red). Parentheses, estimated values ​​of ω and percentage of sites subjected to positive selection. Scale bar, number of overrides per site. (c) Maximum likelihood phylogeny of Myotis PKR transcripts paralogues, with Murine aurata, E. fuscus, Lasiurus borealis And Pipistrellus kuhlii as outgroups (collapsed for viewing). PKR1L and PKR2L may be paralogues or splice variants of PKR1 and PKR2, respectively. Colors indicate duplicate PKRs isolated from an individual. Bootstrap values ​​of ≥0.7 are shown. Scale bar, number of overrides per site. (d) canonical place of EIF2TOK2/PKR in mammals. Genes are shown EIF2AK2 (black and gray arrows), the pseudogene EIF2AK2 (striped arrow) and adjacent genes (white arrows). Genomic coordinates are indicated. (And) Expression pattern of PKR paralogues at baseline and with IFNα treatment by M. velifer fibroblasts. Boxplots represent the number of reads at log scale10 for each condition and PKR copy (for exons found in both genes). Credit: Science Advances (2022). DOI: 10.1126/sciadv.add7540″ width=”800″ height=”500″/>

PKR has been the target of strong positive selection diversifying and original duplication in bats.(a) Sites undergoing positive selection in mammalian protein kinase R (PKR). The graphic panels represent the posterior probabilities of positive selection [Bayes empirical Bayes (BEB)] (yes axis) in the M2 model (ω > 1) for each codon (x axis). Red bars indicate sites with BEB >0.95. The numbers in parentheses are the total species analyzed. Viral antagonists: US11 herpes virus, NS1A influenza A virus (IAV), poxvirus E3 and K3 (green striped boxes), NS5A hepatitis C virus (HCV), and human immunodeficiency virus Tat, reported to interact directly with PKR. (b) Maximum likelihood phylogeny of bat PKR indicating branches undergoing positive selection (P C) Maximum likelihood phylogeny o Myotis Paralogue transcripts of PKR, con Murine aurata, E. fucus, Lasiurus borealisAnd Pipistrellus kuhlii as outgroups (collapsed for viewing). PKR1L and PKR2L may be paralogues or splice variants of PKR1 and PKR2, respectively. Colors indicate duplicate PKRs isolated from an individual. Bootstrap values ​​of ≥0.7 are shown. Scale bar, number of overrides per site. (d) Canonical place or FEI2aK2/PKR in mammals. The EIF2AK2 genes (black and gray arrows), the EIF2AK2 pseudogene (striped arrow) and adjacent genes (white arrows). Genomic coordinates are indicated. (And) Expression pattern of PKR paralogues at baseline and IFNα treatment of M Velifer fibroblasts. Box plots represent the number of reads in the log10 scale for each condition and PKR copy (for exons found in both genes). Credit: The progress of science (2022). DOI: 10.1126/sciadv.add7540

An international team of researchers has found evidence of repeated genomic duplication and genetic diversification in protein kinase R (PKR) in mouse-eared bats. In their article published in the magazine The progress of sciencethe team describes their genomic study of multiple mouse-eared bat species and their sequencing of 15 of them.

Previous research has shown that bats can harbor many viral infections that do not harm them – one of the reasons they have been identified as vectors for viruses that pass on to other animals and/or humans. In this new effort, the researchers set out to learn more about why bats are able to remain unharmed when infected with viruses that harm most other mammals.

The team’s work focused mainly on PKR, a protein encoded by the EIF2AK2 gene. Previous research has shown that it is an important part of immune responses to viruses in mammals. To learn more about how it works in bats compared to other mammals, the researchers looked at the gene sequences of 33 species of mouse-eared bats.

They focused more specifically on differences in EIF2AK2, which translate into differences in PKR, which in turn represent different virus-fighting abilities. The team also sequenced the genomes of 15 species to gain a broader perspective on the role EIF2AK2 has played in the history of the mouse-eared bat.

The researchers found evidence of what they describe as an arms race between EIF2AK2 and various viruses. And as part of that arms race, duplication appeared at some point. EIF2AK2 started appearing twice in the genome, which made it possible to create two different types of PKR in each bat studied. And the two versions didn’t just double kill the virus; they were slightly different, allowing their host bat to fight off a virus in two ways. And that, the researchers suggest, is probably why bats are able to harbor viruses without getting sick.

The researchers also found some species that had more than two copies of EIF2AK2 and, in some cases, other genes that were very similar to EIF2AK2. Either way, it likely makes bats even more capable of fighting viruses. They also noted that such duplications are only found in bats so far.

More information:
Stéphanie Jacquet et al, Adaptive duplication and genetic diversification of protein kinase R contribute to the specificity of bat-virus interactions, The progress of science (2022). DOI: 10.1126/sciadv.add7540

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Citation: Researchers find repeated gene duplications and genetic diversification in protein kinase R in mouse-eared bats (2022, Nov 25) retrieved Nov 25, 2022 from https://phys.org/news/2022-11-gene-duplications- genetic-diversification protein.html

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