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

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 t

SUBMITTER: Kang Y 

PROVIDER: S-EPMC316956 | biostudies-literature | 1999 May

REPOSITORIES: biostudies-literature