title: Restrictive influence of SAMHD1 on Hepatitis B Virus life cycle.
abstract: Deoxynucleotide triphosphates (dNTPs) are essential for efficient hepatitis B virus (HBV) replication. Here, we investigated the influence of the restriction factor SAMHD1, a dNTP hydrolase (dNTPase) and RNase, on HBV replication. We demonstrated that silencing of SAMHD1 in hepatic cells increased HBV replication, while overexpression had the opposite effect. SAMHD1 significantly affected the levels of extracellular viral DNA as well as intracellular reverse transcription products, without affecting HBV RNAs or cccDNA. SAMHD1 mutations that interfere with the dNTPase activity (D137N) or in the catalytic center of the histidine-aspartate (HD) domain (D311A), and a phospho-mimetic mutation (T592E), abrogated the inhibitory activity. In contrast, a mutation diminishing the potential RNase but not dNTPase activity (Q548A) and a mutation disabling phosphorylation (T592A) did not affect antiviral activity. Moreover, HBV restriction by SAMHD1 was rescued by addition of deoxynucleosides. Although HBV infection did not directly affect protein level or phosphorylation of SAMHD1, the virus upregulated intracellular dATPs. Interestingly, SAMHD1 was dephosphorylated, thus in a potentially antiviral-active state, in primary human hepatocytes. Furthermore, SAMHD1 was upregulated by type I and II interferons in hepatic cells. These results suggest that SAMHD1 is a relevant restriction factor for HBV and restricts reverse transcription through its dNTPase activity.
authors.affiliation: Host-Pathogen Interactions, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Andreas F R
authors.initials: AF
authors.lastname: Sommer
authors.affiliation: Host-Pathogen Interactions, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Lise
authors.initials: L
authors.lastname: Rivière
authors.affiliation: Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Bingqian
authors.initials: B
authors.lastname: Qu
authors.affiliation: Host-Pathogen Interactions, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Schott
authors.affiliation: Host-Pathogen Interactions, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Riess
authors.affiliation: Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ni
authors.affiliation: Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, USA.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Shepard
authors.affiliation: Host-Pathogen Interactions, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Esther
authors.initials: E
authors.lastname: Schnellbächer
authors.affiliation: Division of Virology, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Malin
authors.initials: M
authors.lastname: Finkernagel
authors.affiliation: Division of Virology, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Himmelsbach
authors.affiliation: Division of Medical Biotechnology, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Welzel
authors.affiliation: Division of Virology, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Nadja
authors.initials: N
authors.lastname: Kettern
authors.affiliation: Division of Virology, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Donnerhak
authors.affiliation: Clinic for Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Münk
authors.affiliation: Division of Medical Biotechnology, Paul-Ehrlich-Institute, Langen, Germany.
authors.forename: Egbert
authors.initials: E
authors.lastname: Flory
authors.affiliation: General and Visceral Surgery, Goethe-University, Frankfurt, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Liese
authors.affiliation: Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, USA.
authors.forename: Baek
authors.initials: B
authors.lastname: Kim
authors.affiliation: Department of Infectious Diseases, Molecular Virology, University Hospital Heidelberg, Heidelberg, Germany.|German Center for Infection Research (DZIF), Heidelberg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Urban
authors.affiliation: Host-Pathogen Interactions, Paul-Ehrlich-Institute, Langen, Germany.|Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.|German Center for Infection Research (DZIF), Langen, Germany.
authors.forename: Renate
authors.initials: R
authors.lastname: König
mesh_terms: D019943:Amino Acid Substitution; D056945:Hep G2 Cells; D006515:Hepatitis B virus / Q000502:physiology*; D022781:Hepatocytes / Q000201:enzymology / Q000473:pathology / Q000821:virology; D006801:Humans; D020125:Mutation, Missense; D000076106:SAM Domain and HD Domain-Containing Protein 1 / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology*
chemical_list: D000076106:SAM Domain and HD Domain-Containing Protein 1; C484280:SAMHD1 protein, human