TY - JOUR
T1 - Helicases DDX5 and DDX17 promote heterogeneity in HBV transcription termination in infected human hepatocytes
AU - Chapus, Fleur
AU - Giraud, Guillaume
AU - Huchon, Pélagie
AU - Rodà, Mélanie
AU - Grand, Xavier
AU - Charre, Caroline
AU - Goldsmith, Chloé
AU - Roca Suarez, Armando Andres
AU - Martinez, Maria Guadalupe
AU - Fresquet, Judith
AU - Diederichs, Audrey
AU - Locatelli, Maëlle
AU - Polvèche, Hélène
AU - Scholtès, Caroline
AU - Chemin, Isabelle
AU - Hernandez Vargas, Hector
AU - Rivoire, Michel
AU - Bourgeois, Cyril F.
AU - Zoulim, Fabien
AU - Testoni, Barbara
PY - 2024
Y1 - 2024
N2 - Background & Aims: Transcription termination fine-tunes gene expression and contributes to the specification of RNA function in eukaryotic cells. Transcription termination of HBV is subject to the recognition of the canonical polyadenylation signal (cPAS) common to all viral transcripts. However, the regulation of this cPAS and its impact on viral gene expression and replication is currently unknown. Methods: To unravel the regulation of HBV transcript termination, we implemented a 3’ RACE (rapid amplification of cDNA ends)-PCR assay coupled to single molecule sequencing both in in vitro-infected hepatocytes and in chronically infected patients. Results: The detection of a previously unidentified transcriptional readthrough indicated that the cPAS was not systematically recognized during HBV replication in vitro and in vivo. Gene expression downregulation experiments demonstrated a role for the RNA helicases DDX5 and DDX17 in promoting viral transcriptional readthrough, which was, in turn, associated with HBV RNA destabilization and decreased HBx protein expression. RNA and chromatin immunoprecipitation, together with mutation of the cPAS sequence, suggested a direct role of DDX5 and DDX17 in functionally linking cPAS recognition to transcriptional readthrough, HBV RNA stability and replication. Conclusions: Our findings identify DDX5 and DDX17 as crucial determinants of HBV transcriptional fidelity and as host restriction factors for HBV replication. Impact and implications: HBV covalently closed circular (ccc)DNA degradation or functional inactivation remains the holy grail for the achievement of HBV cure. Transcriptional fidelity is a cornerstone in the regulation of gene expression. Here, we demonstrate that two helicases, DDX5 and DDX17, inhibit recognition of the HBV polyadenylation signal and thereby transcriptional termination, thus decreasing HBV RNA stability and acting as restriction factors for efficient cccDNA transcription and viral replication. The observation that DDX5 and DDX17 are downregulated in patients chronically infected with HBV suggests a role for these helicases in HBV persistence in vivo. These results open new perspectives for researchers aiming at identifying new targets to neutralise cccDNA transcription.
AB - Background & Aims: Transcription termination fine-tunes gene expression and contributes to the specification of RNA function in eukaryotic cells. Transcription termination of HBV is subject to the recognition of the canonical polyadenylation signal (cPAS) common to all viral transcripts. However, the regulation of this cPAS and its impact on viral gene expression and replication is currently unknown. Methods: To unravel the regulation of HBV transcript termination, we implemented a 3’ RACE (rapid amplification of cDNA ends)-PCR assay coupled to single molecule sequencing both in in vitro-infected hepatocytes and in chronically infected patients. Results: The detection of a previously unidentified transcriptional readthrough indicated that the cPAS was not systematically recognized during HBV replication in vitro and in vivo. Gene expression downregulation experiments demonstrated a role for the RNA helicases DDX5 and DDX17 in promoting viral transcriptional readthrough, which was, in turn, associated with HBV RNA destabilization and decreased HBx protein expression. RNA and chromatin immunoprecipitation, together with mutation of the cPAS sequence, suggested a direct role of DDX5 and DDX17 in functionally linking cPAS recognition to transcriptional readthrough, HBV RNA stability and replication. Conclusions: Our findings identify DDX5 and DDX17 as crucial determinants of HBV transcriptional fidelity and as host restriction factors for HBV replication. Impact and implications: HBV covalently closed circular (ccc)DNA degradation or functional inactivation remains the holy grail for the achievement of HBV cure. Transcriptional fidelity is a cornerstone in the regulation of gene expression. Here, we demonstrate that two helicases, DDX5 and DDX17, inhibit recognition of the HBV polyadenylation signal and thereby transcriptional termination, thus decreasing HBV RNA stability and acting as restriction factors for efficient cccDNA transcription and viral replication. The observation that DDX5 and DDX17 are downregulated in patients chronically infected with HBV suggests a role for these helicases in HBV persistence in vivo. These results open new perspectives for researchers aiming at identifying new targets to neutralise cccDNA transcription.
KW - HBV
KW - RNA helicases
KW - RNA polyadenylation
KW - RNA stability
KW - transcription termination
UR - http://www.scopus.com/inward/record.url?scp=85196944719&partnerID=8YFLogxK
U2 - 10.1016/j.jhep.2024.05.016
DO - 10.1016/j.jhep.2024.05.016
M3 - Article
C2 - 38782119
AN - SCOPUS:85196944719
SN - 0168-8278
VL - 81
SP - 609
EP - 620
JO - Journal of Hepatology
JF - Journal of Hepatology
IS - 4
ER -