Phosphorylation regulates RNA binding by the human T-cell leukemia virus Rex protein

P. L. Green, M. T. Yip, Y. Xie, I. S.Y. Chen

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Abstract

The Rex protein of human T-cell leukemia virus types I (HTLV-I) and II (HTLV-II) regulates the expression of the viral structural genes and is critical for viral replication. Rex acts by specifically binding to RNAs containing sequences of the R region of the 5' long terminal repeat. Two forms of Rex detected in HTLV-II-infected cells, p26(rex) and p24(rex), differ in the extent of serine phosphorylation. Two-dimensional phosphopeptide analysis indicates that p26(rex) is extensively phosphorylated at multiple sites. Using a sensitive immunobinding assay, we show that the phosphorylation state of Rex determines the efficiency of binding of Rex to HTLV-II target RNAs. Thus, the phosphorylation state of Rex in the infected cell may be a switch that determines whether virus exists in a latent or productive state. These studies also suggest that phosphorylation of RNA- binding regulatory proteins is a more general mechanism of gene regulation.

Original languageEnglish (US)
Pages (from-to)4325-4330
Number of pages6
JournalJournal of virology
Volume66
Issue number7
StatePublished - Jan 1 1992

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ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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