Differential Requirements for Alternative Splicing and Nuclear Export Functions of Equine Infectious Anemia Virus Rev Protein

AUTOR(ES)

Harris, Matthew E.

FONTE

American Society for Microbiology

RESUMO

The Rev protein of equine infectious anemia virus (ERev) exports unspliced and partially spliced viral RNAs from the nucleus. Like several cellular proteins, ERev regulates its own mRNA by mediating an alternative splicing event. To determine the requirements for these functions, we have identified ERev mutants that affect RNA export or both export and alternative splicing. Mutants were further characterized for subcellular localization, nuclear-cytoplasmic shuttling, and multimerization. None of the nuclear export signal (NES) mutants are defective for alternative splicing. Furthermore, the NES of ERev is similar in composition but distinct in spacing from other leucine-rich NESs. Basic residues at the C terminus of ERev are involved in nuclear localization, and disruption of the C-terminal residues affects both functions of ERev. ERev forms multimers, and no mutation disrupts this activity. In two mutants with substitutions of charged residues in the middle of ERev, RNA export is affected. One of these mutants is also defective for ERev-mediated alternative splicing but is identical to wild-type ERev in its localization, shuttling, and multimerization. Together, these results demonstrate that the two functions of ERev both require nuclear import and at least one other common activity, but RNA export can be separated from alternative splicing based on its requirement for a functional NES.

Documentos Relacionados

• Binding of Equine Infectious Anemia Virus Rev to an Exon Splicing Enhancer Mediates Alternative Splicing and Nuclear Export of Viral mRNAs
• Equine infectious anemia virus trans-regulatory protein Rev controls viral mRNA stability, accumulation, and alternative splicing.
• Nuclear transport of human immunodeficiency virus type 1, visna virus, and equine infectious anemia virus Rev proteins: identification of a family of transferable nuclear export signals.
• Biological Characterization of Rev Variation in Equine Infectious Anemia Virus
• Reconstitution of HIV-1 Rev nuclear export: Independent requirements for nuclear import and export