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KAP1-mediated epigenetic suppression in anti-RNA viral responses by direct targeting RIG-I and MDA5

ABSTRACT: Retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), including RIG-I (encoded by Ddx58) and MDA5 (melanoma-differentiation-associated gene 5, encoded by Ifih1), are crucial for initiating antiviral responses. Endogenous retroviral elements (ERVs) are transposable elements derived from exogenous retrovirus that integrated into the genome. KRAB-associated protein 1 (KAP1) is a master epigenetic suppressor of ERVs, and thereby protects cells from detrimental genome instability. Increased ERV transcripts are sensed by RLRs and trigger innate immune signaling. However, whether KAP1 could directly control RLRs activity remain unclear. Here we show that KAP1 attenuates RNA viral infection induced type I IFNs and facilitates viral replication by inhibiting RIG-I/MDA5 expression in primary peritoneal macrophages of C57BL/6J mice. Kap1 deficiency increased IFN-β expression and inhibited VSV replication in C57BL/6J mice in vivo. Mechanistically, KAP1 binds to the promoter regions of Ddx58 and Ifih1, and promotes the establishment of repressive histone marks in primary peritoneal macrophages of C57BL/6J mice. Concordantly, KAP1 suppresses the expression of RIG-I and MDA5 at transcriptional level in primary peritoneal macrophages of C57BL/6J mice. Our results establish that KAP1 epigenetically suppresses host antiviral responses by direct targeting RIG-1 and MDA5, and thus facilitates the immune escape of RNA viruses.

ORGANISM(S): Mus musculus

PROVIDER: GSE178443 | GEO | 2021/07/28

REPOSITORIES: GEO

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