Selective nuclear export of specific classes of mRNA from mammalian nuclei is promoted by GANP

The nuclear phase of the gene expression pathway culminates in the export of mature mRNAs to the cytoplasm through nuclear pore complexes (NPCs). GANP (Germinal-centre Associated Nuclear Protein) promotes the transfer to NPCs of mRNAs bound to the transport factor NXF1. Here, we demonstrate that GANP, subunit of the TREX-2 mRNA export complex, promotes selective nuclear export of a specific subset of mRNAs whose transport depends on NXF1. Genome-wide gene expression profiling showed that half of the transcripts whose nuclear export was impaired following NXF1 depletion also showed reduced export when GANP was depleted. GANP-dependent transcripts were highly expressed, yet short-lived, and were highly enriched in those encoding central components of the gene expression machinery such as RNA synthesis and processing factors. After injection into Xenopus oocyte nuclei, representative GANP-dependent transcripts showed faster nuclear export kinetics than representative transcripts that were not influenced by GANP depletion. We propose that GANP promotes the nuclear export of specific classes of mRNAs that may facilitate rapid changes in gene expression. We used gene expression profiling to compare the abundance of cytoplasmic RNAs after GANP or NXF1 depletion