TY - JOUR
T1 - Activation of RNase L by murine coronavirus in myeloid cells is dependent on basal Oas gene expression and independent of virus-induced interferon
AU - Birdwell, L. Dillon
AU - Zalinger, Zachary B.
AU - Li, Yize
AU - Wright, Patrick W.
AU - Elliott, Ruth
AU - Rose, Kristine M.
AU - Silverman, Robert H.
AU - Weiss, Susan R.
N1 - Funding Information:
HHS | NIH | National Cancer Institute (NCI) provided funding to Robert H. Silverman under grant number R01-CA044059. HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID) provided funding to L. Dillon Birdwell, Yize Li, Ruth Elliott, Kristine M. Rose, Robert H. Silverman, and Susan R. Weiss under grant numbers R01-AI104887 and T32-AI007324. HHS | NIH | National Institute of Neurological Disorders and Stroke (NINDS) provided funding to L. Dillon Birdwell, Zachary Bestor Zalinger, Yize Li, Ruth Elliott, Kristine M. Rose, and Susan R. Weiss under grant numbers R01-NS081008, R01-NS054695, and T32-NS-007180.
Publisher Copyright:
© 2016, American Society for Microbiology.
PY - 2016
Y1 - 2016
N2 - The oligoadenylate synthetase (OAS)-RNase L pathway is a potent interferon (IFN)-induced antiviral activity. Upon sensing double-stranded RNA, OAS produces 2',5'-oligoadenylates (2-5A), which activate RNase L. Murine coronavirus (mouse hepatitis virus [MHV]) nonstructural protein 2 (ns2) is a 2',5'-phosphodiesterase (PDE) that cleaves 2-5A, thereby antagonizing RNase L activation. PDE activity is required for robust replication in myeloid cells, as a mutant of MHV (ns2H126R) encoding an inactive PDE fails to antagonize RNase L activation and replicates poorly in bone marrow-derived macrophages (BMM), while ns2H126R replicates to high titer in several types of nonmyeloid cells, as well as in IFN receptor-deficient (Ifnar1-/-) BMM. We reported previously that myeloid cells express significantly higher basal levels of OAS transcripts than nonmyeloid cells. Here, we investigated the contributions of Oas gene expression, basal IFN signaling, and virus-induced IFN to RNase L activation. Infection with ns2H126R activated RNase L in Ifih1-/- BMM to a similar extent as in wild-type (WT) BMM, despite the lack of IFN induction in the absence of MDA5 expression. However, ns2H126R failed to induce RNase L activation in BMM treated with IFNAR1-blocking antibody, as well as in Ifnar1-/- BMM, both expressing low basal levels of Oas genes. Thus, activation of RNase L does not require virus-induced IFN but rather correlates with adequate levels of basal Oas gene expression, maintained by basal IFN signaling. Finally, overexpression of RNase L is not sufficient to compensate for inadequate basal OAS levels.
AB - The oligoadenylate synthetase (OAS)-RNase L pathway is a potent interferon (IFN)-induced antiviral activity. Upon sensing double-stranded RNA, OAS produces 2',5'-oligoadenylates (2-5A), which activate RNase L. Murine coronavirus (mouse hepatitis virus [MHV]) nonstructural protein 2 (ns2) is a 2',5'-phosphodiesterase (PDE) that cleaves 2-5A, thereby antagonizing RNase L activation. PDE activity is required for robust replication in myeloid cells, as a mutant of MHV (ns2H126R) encoding an inactive PDE fails to antagonize RNase L activation and replicates poorly in bone marrow-derived macrophages (BMM), while ns2H126R replicates to high titer in several types of nonmyeloid cells, as well as in IFN receptor-deficient (Ifnar1-/-) BMM. We reported previously that myeloid cells express significantly higher basal levels of OAS transcripts than nonmyeloid cells. Here, we investigated the contributions of Oas gene expression, basal IFN signaling, and virus-induced IFN to RNase L activation. Infection with ns2H126R activated RNase L in Ifih1-/- BMM to a similar extent as in wild-type (WT) BMM, despite the lack of IFN induction in the absence of MDA5 expression. However, ns2H126R failed to induce RNase L activation in BMM treated with IFNAR1-blocking antibody, as well as in Ifnar1-/- BMM, both expressing low basal levels of Oas genes. Thus, activation of RNase L does not require virus-induced IFN but rather correlates with adequate levels of basal Oas gene expression, maintained by basal IFN signaling. Finally, overexpression of RNase L is not sufficient to compensate for inadequate basal OAS levels.
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U2 - 10.1128/JVI.03036-15
DO - 10.1128/JVI.03036-15
M3 - Article
C2 - 26739051
AN - SCOPUS:84961158252
SN - 0022-538X
VL - 90
SP - 3160
EP - 3172
JO - Journal of virology
JF - Journal of virology
IS - 6
ER -