ABSTRACT; ; Background; ; Bats are a major reservoir of zoonotic viruses, and there has been growing interest in characterizing bat-specific features of innate immunity and inflammation. Recent studies have revealed bat-specific adaptations affecting interferon (IFN) signaling and IFN- stimulated genes (ISGs), but we still have a limited understanding of the genetic mechanisms that have shaped the evolution of bat immunity. Here we investigated the transcriptional and epigenetic dynamics of transposable elements (TEs) during the type I IFN response in little brown bat (; Myotis lucifugus; ) primary embryonic fibroblast cells, using RNA-seq and CUT&RUN.; ; ; ; Results; ; We found multiple bat-specific TEs that undergo both locus-specific and family-level transcriptional induction in response to IFN. Our transcriptome reassembly identified multiple ISGs that have acquired novel exons from bat-specific TEs, including; NLRC5; ,; SLNF5; and a previously unannotated isoform of the; IFITM2; gene. We also identified examples of TE-derived regulatory elements, but did not find strong evidence supporting genome-wide epigenetic activation of TEs in response to IFN.; ; ; ; Conclusion; ; Collectively, our study uncovers numerous TE-derived transcripts, proteins, and alternative isoforms that are induced by IFN in; Myotis lucifugus; cells, highlighting candidate loci that may contribute to bat-specific immune function.; ;
