A novel CRM1-dependent nuclear export signal in adenoviral E1A protein regulated by phosphorylation

Hong Jiang, Melissa V. Olson, Diana R. Medrano, Ok Hee Lee, Jing Xu, Yuji Piao, Marta M. Alonso, Candelaria Gomez-Manzano, Mien Chie Hung, W. K.Alfred Yung, Juan Fueyo

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Adenoviral E1A is a versatile protein that can reprogram host cells for efficient viral replication. The nuclear import of E1A is mediated by a nuclear localization signal; however, whether E1A can be actively exported from the nucleus is unknown. We first reported a CRM1-dependent nuclear export signal (NES) in E1A that is conserved in the group C adenoviruses. We showed that CRM1 and E1A coimmunoprecipitated and that blockage of CRM1 function by leptomycin B or small interfering RNA resulted in the nuclear localization of E1A. Through mutational analyses, we identified an active canonical NES element within the E1A protein spanning amino acids 70-80. We further demonstrated that phosphorylation of adjacent serine (S)89 resulted in the cytoplasmic accumulation of E1A. Interestingly, coincident with the accumulation of cells in the S/G2/M phase and histone H1 phosphorylation, E1A was relocated to the cytoplasm at the late stage of the viral cycle, which was blocked by the CDC2/CDK2 inhibitor roscovitine. Importantly, titration of the progenies of the viruses in infected cells showed that the replication efficiency of the NES mutant adenovirus was up to 500-fold lower than that of the wild-type adenovirus. Collectively, our data demonstrate the existence of a NES in E1A that is modulated by the phosphorylation of the S89 residue and the NES plays a role for an efficient viral replication in the host cells.

Original languageEnglish (US)
Pages (from-to)E2098-E2107
JournalFASEB Journal
Issue number14
StatePublished - Dec 2006
Externally publishedYes


  • Leptomycin B
  • NES
  • NLS

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics


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