Nuclear RNA Export Factor 4 (NXF4)

Export of mRNAs from the nucleus involves a number of proteins, including nucleoporins, RNA-binding proteins, an RNA helicase (DDX19), and nuclear pore complex-associated proteins, such as NXF1 and RAE1 .By searching EST databases for homologs of NXF1 and by RT-PCR analysis, Herold et al. (2000) obtained cDNAs encoding NXF2, NXF3, NXF4, and NXF5. The deduced 579-amino acid NXF4 protein has the conserved domain structure of NXF1, including a noncanonical RNP-type RNA-binding domain (RBD), 4 leucine-rich repeats (LRRs), a nuclear transport factor-2 (NTF2)-like domain that allows heterodimerization with NTF2-related export protein-1 (NXT1), and a ubiquitin-associated domain that mediates interactions with nucleoporins. Using genomic sequence analysis, Herold et al. (2000) mapped the NXF4 gene to Xq22.1-q22.3 and determined that it contains at least 20 exons.