Abstract

Cytosolic DNA that emerges during infection with a retrovirus or DNA virus triggers antiviral type I interferon responses. So far, only double-stranded DNA (dsDNA) over 40 base pairs (bp) in length has been considered immunostimulatory. Here we found that unpaired DNA nucleotides flanking short base-paired DNA stretches, as in stem-loop structures of single-stranded DNA (ssDNA) derived from human immunodeficiency virus type 1 (HIV-1), activated the type I interferon–inducing DNA sensor cGAS in a sequence-dependent manner. DNA structures containing unpaired guanosines flanking short (12- to 20-bp) dsDNA (Y-form DNA) were highly stimulatory and specifically enhanced the enzymatic activity of cGAS. Furthermore, we found that primary HIV-1 reverse transcripts represented the predominant viral cytosolic DNA species during early infection of macrophages and that these ssDNAs were highly immunostimulatory. Collectively, our study identifies unpaired guanosines in Y-form DNA as a highly active, minimal cGAS recognition motif that enables detection of HIV-1 ssDNA.

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NCBI Reference Sequence

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Acknowledgements

We thank C. Siering for help with circular dichroism spectroscopy, and S. Schmitt for discussions. Supported by Deutsche Forschungsgemeinschaft (SFB670 to M.S., W.B., V.H. and G.H.; DFG SCHL1930/1–1 to M.S.; SFB704 to G.H., V.H. and W.B.; and SFB832 and KFO177 to C.C. and G.H.), the Deutsche Forschungsgemeinschaft Excellence Cluster ImmunoSensation (G.H., M.S., V.H., E.B. and W.B.), BONFOR of the University of Bonn (E.B.) and the German Center of Infectious Disease (G.H., V.H. and W.B.).

Author information

Author notes

    • Cristina Amparo Hagmann
    •  & Damian Ackermann

    Present addresses: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA (C.A.H.), and Microsynth, Balgach, Switzerland (D.A.).

    • Anna-Maria Herzner
    • , Cristina Amparo Hagmann
    • , Gunther Hartmann
    •  & Martin Schlee

    These authors contributed equally to this work.

Affiliations

  1. Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, Bonn, Germany.

    • Anna-Maria Herzner
    • , Cristina Amparo Hagmann
    • , Marion Goldeck
    • , Steven Wolter
    • , Christina Mertens
    • , Thomas Zillinger
    • , Eva Bartok
    • , Christoph Coch
    • , Janos Ludwig
    • , Winfried Barchet
    • , Gunther Hartmann
    •  & Martin Schlee
  2. Department of Obstetrics and Gynecology, Center for Integrated Oncology, University of Bonn, Bonn, Germany.

    • Kirsten Kübler
  3. Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.

    • Sabine Wittmann
    •  & Thomas Gramberg
  4. Department Biochemistry, Gene Center, Ludwig-Maximilians University, Munich, Germany.

    • Liudmila Andreeva
    •  & Karl-Peter Hopfner
  5. German Center of Infectious Disease, Cologne-Bonn, Germany.

    • Thomas Zillinger
    •  & Winfried Barchet
  6. School of Life Sciences, University of Science and Technology of China, Hefei, China.

    • Tengchuan Jin
  7. Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA.

    • Tsan Sam Xiao
  8. LIMES Institute, Chemical Biology, University of Bonn, Bonn, Germany.

    • Damian Ackermann
  9. Institute of Molecular Medicine, University Hospital, University of Bonn, Bonn, Germany.

    • Veit Hornung

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Contributions

M.S., A.-M.H., J.L., C.A.H. and G.H., conceptualization; M.S., A.-M.H., C.A.H., M.G., S. Wolter, K.K., T.G., L.A., K.-P.H., T.Z., C.M., T.J., T.S.X. and D.A., methodology; A.-M.H., C.A.H., M.G., D.A., T.J., T.S.X. and M.S., formal analysis; A.-M.H., M.S., C.A.H., M.G., S. Wolter, T.G., L.A., T.Z., C.M. and T.J., investigation; M.S., A.-M.H., E.B., C.A.H., V.H., W.B. and G.H., writing of the original draft; A.-M.H., M.S., E.B., W.B., C.C. and G.H., writing (review and editing); M.S., G.H., V.H., W.B., C.C., E.B., K.-P.H. and T.G., funding acquisition; T.J., T.S.X., S. Wittmann, T.G., L.A. and K.-P.H., resources; and M.S., T.G., K.-P.H., C.C., W.B. and G.H., supervision.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Anna-Maria Herzner or Martin Schlee.

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    Supplementary Figures 1–6

Excel files

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    Supplementary Table 1

    Sequences of indicated DNA-structures

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    Supplementary Table 2

    Primers sequences

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DOI

https://doi.org/10.1038/ni.3267

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