title: Host factor PRPF31 is involved in cccDNA production in HBV-replicating cells.
abstract: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) plays a central role in chronic HBV infection and replication, and is an important factor for HBV surface antigen loss indicating the endpoint of HBV treatment. However, there is a known problem that current anti-HBV drugs, including interferons and nucleos(t)ide analogues, reduce HBV replication but have a little or no effect on reducing cccDNA. Therefore, the development of new therapeutic agents is necessary to eradicate cccDNA. In this study, we identified pre-mRNA processing factor 31 (PRPF31) by siRNA screening as a factor associated with cccDNA. PRPF31 knockdown by siRNA decreased cccDNA formation without serious cytotoxicity. In rescue experiments, expression of siRNA-resistant PRPF31 recovered cccDNA formation. PRPF31 knockdown did not affect HBV core protein and HBV core DNA levels in HBV-replicating cells. Chromatin immunoprecipitation and immunoprecipitation assays revealed an association between PRPF31 and cccDNA. Furthermore, co-overexpression of PRPF31 and HBx enhanced cccDNA formation in HepAD38 cells. Taken together, the present findings suggest that the interaction between PRPF31 and HBx may be a novel target for anti-HBV treatment.
authors.affiliation: Central Pharmaceutical Research Institute, Japan Tobacco Inc., Osaka, Japan. Electronic address: wataru.kinoshita@jt.com.
authors.forename: Wataru
authors.initials: W
authors.lastname: Kinoshita
authors.affiliation: Central Pharmaceutical Research Institute, Japan Tobacco Inc., Osaka, Japan. Electronic address: naoki.ogura@jt.com.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ogura
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan. Electronic address: kwatashi@nih.go.jp.
authors.forename: Koichi
authors.initials: K
authors.lastname: Watashi
authors.affiliation: Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan. Electronic address: wakita@nih.go.jp.
authors.forename: Takaji
authors.initials: T
authors.lastname: Wakita
mesh_terms: D002460:Cell Line; D004261:DNA Replication; D004270:DNA, Circular / Q000235:genetics / Q000378:metabolism*; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D056945:Hep G2 Cells; D006509:Hepatitis B / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006515:Hepatitis B virus / Q000235:genetics / Q000502:physiology*; D006801:Humans; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D005136:Eye Proteins; C454222:PRPF31 protein, human; D034741:RNA, Small Interfering
keywords: HBV; PRPF31; cccDNA