RIG-I Detects Kaposi's Sarcoma-Associated Herpesvirus Transcripts in a RNA Polymerase III-Independent Manner

Yugen Zhang; Dirk P Dittmer; Piotr A Mieczkowski; Kurtis M Host; William G Fusco; Joseph A Duncan; Blossom Damania

doi:10.1128/mBio.00823-18

RIG-I Detects Kaposi's Sarcoma-Associated Herpesvirus Transcripts in a RNA Polymerase III-Independent Manner

mBio. 2018 Jul 3;9(4):e00823-18. doi: 10.1128/mBio.00823-18.

Authors

Yugen Zhang^{1

2}, Dirk P Dittmer^{1

2}, Piotr A Mieczkowski^{3

4}, Kurtis M Host^{1

2}, William G Fusco⁵, Joseph A Duncan⁵, Blossom Damania^{6

2}

Affiliations

¹ Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
² Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
³ High Throughput Sequencing Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
⁴ Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
⁵ Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
⁶ Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA damania@med.unc.edu.

Abstract

Retinoic acid-inducible gene I (RIG-I) is a cytosolic pathogen recognition receptor that initiates the innate immune response against many RNA viruses. We previously showed that RIG-I restricts Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation (J. A. West et al., J Virol 88:5778-5787, 2014, https://doi.org/10.1128/JVI.03226-13). In this study, we report that KSHV stimulates the RIG-I signaling pathway in a RNA polymerase (Pol) III-independent manner and subsequently induces type I interferon (IFN) responses. Knockdown or inhibition of RNA Pol III had no effect on beta interferon (IFN-β) induction by KSHV. By using high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation (HITS-CLIP) approach, we identified multiple KSHV regions that give rise to RNA fragments binding to RIG-I, such as ORF8_10420-10496, Repeat region (LIR1)_{119059-119204}, and ORF25_43561-43650 The sequence dissimilarity between these fragments suggests that RIG-I detects a particular structure rather than a specific sequence motif. Synthesized ORF8_10420-10496 RNA stimulated RIG-I-dependent but RNA Pol III-independent IFN-β signaling. In summary, several KSHV RNAs are sensed by RIG-I in a RNA Pol III-independent manner.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Innate immune responses against viral infections, especially the induction of type I interferon, are critical for limiting the replication of viruses. Retinoic acid-inducible gene I (RIG-I), a cytosolic RNA helicase sensor, plays a significant role in the induction of type I interferon responses following viral infection. Here, we identified multiple RNA regions in KSHV as potential virus ligands that bind to RIG-I and stimulate RIG-I-dependent but RNA Pol III-independent IFN-β signaling. Our results expand the role of RIG-I by providing an example of a DNA virus activating a canonical RNA-sensing pathway.

Keywords: Kaposi's sarcoma-associated herpesvirus; RIG-I; innate immunity.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

DEAD Box Protein 58 / metabolism*
HEK293 Cells
Herpesvirus 8, Human / immunology*
Host-Pathogen Interactions*
Humans
Immunity, Innate*
Interferon-beta / metabolism*
RNA Polymerase III / metabolism*
RNA, Viral / metabolism*
Receptors, Immunologic
Signal Transduction

Substances

RNA, Viral
Receptors, Immunologic
Interferon-beta
RNA Polymerase III
RIGI protein, human
DEAD Box Protein 58

Abstract

Publication types

MeSH terms

Substances

Grants and funding