Dual requirement for yeast hnRNP Nab2p in mRNA poly(A) tail length control and nuclear export.

Recent studies of mRNA export factors have provided additional evidence for a mechanistic link between mRNA 3'-end formation and nuclear export. Here, we identify Nab2p as a nuclear poly(A)-binding protein required for both poly(A) tail length control and nuclear export of mRNA. Loss of NAB2 expression leads to hyperadenylation and nuclear accumulation of poly(A)(+) RNA but, in contrast to mRNA export mutants, these defects can be uncoupled in a nab2 mutant strain.