Virus- and Interferon Alpha-Induced Transcriptomes of Cells from the Microbat Myotis daubentonii

Hölzer, Martin; Schoen, Andreas; Wulle, Julia; Müller, Marcel A.; Drosten, Christian; Marz, Manja; Weber, Friedemann

A somewhat surprising finding was the low presence of type I IFN subtypes besides IFNB1. In fact, we could identify only a type I IFN gene with similarity to horse IFNW2 (IFN-u2) as being modestly IFN stimulated at the 6-h time point, where it reached a log2 fold change of 2.23 and a significant p value (see Figure 3 ). Another detectable type I IFN subtype (although it did not reach the significance threshold) was a relative to human IFNA5. Also Shaw et al. did not list any type I IFN in their pan-mammal transcriptome study (Shaw et al., 2017) An interesting feature of our M. daubentonii data was the detection of multiple paralogs of Mx and BST2. In the genome of the related M. lucifugus we identified three and four copies of Mx and BST2, respectively. Based on the M. lucifugus reference genome, M. daubentonii significantly upregulated either all three (Mx) or all four (BST2) genes ( Figure 6A ). Mx (myxovirus resistance protein) is a large cytosolic GTPase with a broad antiviral spectrum (Haller et al., 2015) . Almost all investigated vertebrate species express multiple paralogs (Haller et al., 2015) . Bat Mx proteins (including Mx1 of M. daubentonii) were shown to confer antiviral activity (Fuchs et al., 2017) . BST2 (bone marrow stromal cell antigen 2), also called Tetherin, is an antiviral transmembrane protein tethering enveloped virus particles to the plasma membrane (Douglas et al., 2010) . A search in the annotated genomes of mammals revealed that Yangochiroptera/Vespertilionidae such as Myotis lucifugus, brandtii und davidii, as well as Eptesicus fuscus harbor several copies of the The displayed genes were filtered by an absolute log2-fold change of 2 and an adjusted p value < 0.05. Genes that are similarly regulated at 6 and 24 h post IFN are clustered together. Data are averages from three biological replicates. Genes missing a gene name and a function in the current Ensembl annotation of M. lucifugus were listed by their unique and abbreviated ID numbers: e.g., ''ENSMLUG00000015795'' was shortened to ''15795.'' (B) Venn diagrams showing the numbers of significantly regulated mRNAs at the two time points of IFN treatment. (C) Expression box plots of selected mRNAs that responded significantly to Clone 13 treatment but not to control and IFN-stimulated conditions. The plots show the DESeq2-normalized expression values for each condition and biological replicate. Graphs show mean values and standard deviations from the three biological replicates.