The human Tap protein is a nuclear mRNA export factor that contains novel RNA-binding and nucleocytoplasmic transport sequences

Yibin Kang, Bryan R. Cullen

Research output: Contribution to journalArticle

205 Scopus citations

Abstract

The constitutive transport element (CTE) encoded by simian type D retroviruses directs unspliced viral RNAs into a nuclear export pathway that is congruent with the pathway used by cellular mRNAs. Here, we show that quail cells are refractory to CTE function but become highly permissive upon expression of the human Tap protein, a candidate CTE cofactor. Tap contains a novel sequence-specific RNA binding domain that is sufficient for CTE binding but inadequate to support CTE function. Using microinjection assays, we have defined two NLSs and one NES in Tap. Mutational inactivation of the Tap NES, which lies outside the RNA-binding domain, not only blocks Tap function but also generates dominant-negative forms of Tap. Whereas replacement of the Tap NES with the well-defined Rev NES rescues the ability of Tap to support CTE function, this substitution also confers sensitivity to agents that block the activity of Crm1, the Rev NES cofactor. Together, these data validate Tap as the first human sequence-specific nuclear mRNA export factor and identify a novel type of NES that can support nuclear mRNA export but does not act via Crm1.

Original languageEnglish (US)
Pages (from-to)1126-1139
Number of pages14
JournalGenes and Development
Volume13
Issue number9
DOIs
StatePublished - May 1 1999

All Science Journal Classification (ASJC) codes

  • Genetics
  • Developmental Biology

Keywords

  • Constitutive transport element
  • Nuclear export
  • Nuclear import
  • Retroviral
  • mRNA

Fingerprint Dive into the research topics of 'The human Tap protein is a nuclear mRNA export factor that contains novel RNA-binding and nucleocytoplasmic transport sequences'. Together they form a unique fingerprint.

  • Cite this