Mycobacterial and HIV infections up-regulated human zinc finger protein 134, a novel positive regulator of HIV-1 LTR activity and viral propagation.

Abstract

BACKGROUND: Concurrent occurrence of HIV and Tuberculosis (TB) infections influence the cellular environment of the host for synergistic existence. An elementary approach to understand such coalition at the molecular level is to understand the interactions of the host and the viral factors that subsequently effect viral replication. Long terminal repeats (LTR) of HIV genome serve as a template for binding trans-acting viral and cellular factors that regulate its transcriptional activity, thereby, deciding the fate of HIV pathogenesis, making it an ideal system to explore the interplay between HIV and the host. METHODOLOGY/PRINCIPAL FINDINGS: In this study, using biotinylated full length HIV-1 LTR sequence as bait followed by MALDI analyses, we identified and further characterized human-Zinc-finger-protein-134 (hZNF-134) as a novel positive regulator of HIV-1 that promoted LTR-driven transcription and viral production. Over-expression of hZNF-134 promoted LTR driven luciferase activity and viral transcripts, resulting in increased virus production while siRNA mediated knockdown reduced both the viral transcripts and the viral titers, establishing hZNF-134 as a positive effector of HIV-1. HIV, Mycobacteria and HIV-TB co-infections increased hZNF-134 expressions in PBMCs, the impact being highest by mycobacteria. Corroborating these observations, primary TB patients (n = 22) recorded extraordinarily high transcript levels of hZNF-134 as compared to healthy controls (n = 16). CONCLUSIONS/SIGNIFICANCE: With these observations, it was concluded that hZNF-134, which promoted HIV-1 LTR activity acted as a positive regulator of HIV propagation in human host. High titers of hZNF-134 transcripts in TB patients suggest that up-regulation of such positive effectors of HIV-1 upon mycobacterial infection can be yet another mechanism by which mycobacteria assists HIV-1 propagation during HIV-TB co-infections. hZNF-134, an uncharacterized host protein, thus assumes a novel regulatory role during HIV-host interactions. Our study provides new insights into the emerging role of zinc finger proteins in HIV-1 pathogenesis.