Dengue NS3, an RNAi suppressor, modulates the human miRNA pathways through its interacting partner.

Abstract

RNAi acts as a host immune response against non-self molecules, including viruses. Viruses evolved to neutralize this response by expressing suppressor proteins. In the present study, we investigated dengue virus non structural protein 3 (dvNS3), for its RNAi-suppressor activity in human cell lines. Dengue virus (DV) NS3 reverts the GFP expression in GFP-silenced cell lines. Pull-down assays of dvNS3 revealed that it interacts with the host factor human heat shock cognate 70 (hHSC70). Down-regulation of hHSC70 resulted in accumulation of dengue viral genomic RNA. Also, the interaction of dvNS3 with hHSC70 perturbs the formation of RISC (RNA-induced silencing complex)-loading complex (RLC), by displacing TRBP (TAR RNA-binding protein) and possibly impairing the downstream activity of miRNAs. Interestingly, some of these miRNAs have earlier been reported to be down-regulated upon DV infection in Huh7 cells. Further studies on the miRNA-mRNA relationship along with mRNA profiling of samples overexpressing dvNS3 revealed up-regulation of TAZ (tafazzin) and SYNGR1 (synaptogyrin 1), known dengue viral host factors (DVHFs). Importantly, overexpression of dvNS3 in human embryonic kidney (HEK) 293T cells resulted in modulation of both mature and precursor miRNAs in human cell lines. Subsequent analysis suggested that dvNS3 induced stage-specific down-regulation of miRNAs. Taken together, these results suggest that dvNS3 affects biogenesis and function of host miRNAs to regulate DVHFs for favouring DV replication.

• Authors: Pavan Kumar Kakumani, K S Rajgokul, Sanket Singh Ponia, Inderjeet Kaur, Srikrishna Mahanty, Guruprasad R Medigeshi, Akhil C Banerjea, Arun Prasad Chopra, Pawan Malhotra, Sunil K Mukherjee, Raj K Bhatnagar
• Journal: The Biochemical journal (Biochem J) Vol. 471 Issue 1 Pg. 89-99 (Oct 01 2015) ISSN: 1470-8728 [Electronic] England
• PMID: 26221025 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 Authors; published by Portland Press Limited.

Chemical References

• HSC70 Heat-Shock Proteins
• HSPA8 protein, human
• MicroRNAs
• NCOA6 protein, human
• Nuclear Receptor Coactivators
• SYNGR1 protein, human
• Synaptogyrins
• Transcription Factors
• Acyltransferases
• TAFAZZIN protein, human
• Carboxypeptidases
• SCPEP1 protein, human
• NS3 protease, dengue virus
• Serine Endopeptidases

Topics

• Acyltransferases
• Carboxypeptidases (genetics, metabolism)
• Dengue (genetics, metabolism, pathology)
• Dengue Virus (genetics, metabolism)
• HEK293 Cells
• HSC70 Heat-Shock Proteins (genetics, metabolism)
• Humans
• MicroRNAs (genetics, metabolism)
• Nuclear Receptor Coactivators (genetics, metabolism)
• RNA Interference
• Serine Endopeptidases (genetics, metabolism)
• Synaptogyrins (biosynthesis, genetics)
• Transcription Factors (biosynthesis, genetics)