Abstract
BackgroundRecent evidence proposes a novel concept that mammalian natural antisense RNAs play important roles in cellular homeostasis by regulating the expression of several genes. Identification and characterization of retroviral antisense RNA would provide new insights into mechanisms of replication and pathogenesis. HIV-1 encoded-antisense RNAs have been reported, although their structures and functions remain to be studied. We have tried to identify and characterize antisense RNAs of HIV-1 and their function in viral infection.ResultsCharacterization of transcripts of HEK293T cells that were transiently transfected with an expression plasmid with HIV-1NL4–3 DNA in the antisense orientation showed that various antisense transcripts can be expressed. By screening and characterizing antisense RNAs in HIV-1NL4–3-infected cells, we defined the primary structure of a major form of HIV-1 antisense RNAs, which corresponds to a variant of previously reported ASP mRNA. This 2.6 kb RNA was transcribed from the U3 region of the 3′ LTR and terminated at the env region in acutely or chronically infected cell lines and acutely infected human peripheral blood mononuclear cells. Reporter assays clearly demonstrated that the HIV-1 LTR harbours promoter activity in the reverse orientation. Mutation analyses suggested the involvement of NF-κΒ binding sites in the regulation of antisense transcription. The antisense RNA was localized in the nuclei of the infected cells. The expression of this antisense RNA suppressed HIV-1 replication for more than one month. Furthermore, the specific knockdown of this antisense RNA enhanced HIV-1 gene expression and replication.ConclusionsThe results of the present study identified an accurate structure of the major form of antisense RNAs expressed from the HIV-1NL4–3 provirus and demonstrated its nuclear localization. Functional studies collectively demonstrated a new role of the antisense RNA in viral replication. Thus, we suggest a novel viral mechanism that self-limits HIV-1 replication and provides new insight into the viral life cycle.
Highlights
Recent evidence proposes a novel concept that mammalian natural antisense RNAs play important roles in cellular homeostasis by regulating the expression of several genes
We studied the transcripts in HEK293T cells that were transiently transfected with an expression plasmid, pME18S-asHIV, which contains the gag to nef region of HIV-1NL4–3 DNA in the antisense orientation was positioned between the RSV promoter and the SV40 poly (A)
The results indicate that various transcripts can be transcribed from the antisense strand of Human immunodeficiency virus type 1 (HIV-1) DNA
Summary
Recent evidence proposes a novel concept that mammalian natural antisense RNAs play important roles in cellular homeostasis by regulating the expression of several genes. HIV-1 encoded-antisense RNAs have been reported, their structures and functions remain to be studied. We have tried to identify and characterize antisense RNAs of HIV-1 and their function in viral infection. There still remain unanswered questions about the mechanisms of HIV-1 infection and pathogenesis despite advances in the knowledge of many diverse viral functions. Mechanisms for viral latency and Several researchers have embarked on studies to identify HIV-1 antisense RNAs (asRNAs) [7,8,9,10,11]. Miller predicted the existence of a novel gene in the antisense strand of HIV-1, which encodes ASP by a well-conserved open reading frame among many strains of HIV-1 [7]. The primary structure and functions of HIV-1 asRNAs have not been fully clarified, many researchers have proposed the potential importance of the asRNAs [9,12,13,14,15,16,17,18,19,20]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
