Positive and negative modulation of human immunodeficiency virus type 1 Rev function by cis and trans regulators of viral RNA splicing.
Expression of the entire complement of human immunodeficiency virus type 1 (HIV-1) viral proteins depends on the competing activities of viral RNA splicing and export into the cytoplasm by Rev. To investigate the possibility that modulation of viral RNA metabolism may alter Rev function, we analyzed the impact of multiple SR proteins on both processes. While overexpression of several of the SR factors altered splicing of HIV-1 env mRNA, they had disparate effects on Rev function that varied with the cell line used. Subsequent examination of exon splicing enhancer (ESE) and/or silencer (ESS) deletions suggests that the effects of the SR proteins on Rev function are not mediated through interaction with these elements. However, analysis of the deletions did indicate that the ESE and/or ESS does have significant effects on Rev function, with deletion of the ESS augmenting the magnitude of the response to Rev and deletion of the ESE significantly reducing it. In situ hybridization and reverse transcription-PCR indicated that the loss of Rev response upon deletion of the ESE was due to a failure of Rev to induce transport of the unspliced RNA into the cytoplasm. Together, the data indicate that cellular splicing factors and viral regulatory elements can have significant stimulatory and inhibitory effects on Rev function, raising the possibility that cells can be rendered permissive or nonpermissive for virus replication by modulation of splicing activities.
Pongoski
Jodi
J
Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, Canada.
Asai
Kengo
K
Cochrane
Alan
A
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D015694:Gene Products, rev / Q000378:metabolism / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012326:RNA Splicing / Q000502:physiology*; D012333:RNA, Messenger; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000235:genetics; D014779:Virus Replication; D054321:rev Gene Products, Human Immunodeficiency Virus
D015694:Gene Products, rev; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D014759:Viral Envelope Proteins; D054321:rev Gene Products, Human Immunodeficiency Virus