Nup153 and TPR/Megator Interact with TREX-2 Subunits and Are Essential for TREX-2-Dependent Nuclear Export of hsp70 mRNA in Drosophila

The TREX-2 complex is conserved from yeast to humans and is responsible for mRNA export from the nucleus to the cytoplasm. In yeast and humans, the TPR and Nup153 nucleoporins of the nuclear pore complex are involved in TREX-2-dependent mRNA export, but data on their involvement in this process is rather controversial. In the present work, we have studied the role of TPR and Nup153 in the TREX-2-dependent export of hsp70 mRNA in Drosophila. We have shown that Nup153 and TPR are required for the TREX-2-dependent export of hsp70 mRNA, and their knockdown leads to mRNA accumulation in the cell nucleus. We have also demonstrated that Nup153 knockdown leads to TPR relocation to the nucleoplasm. Both nucleoporins are required for TREX-2 subunits’ association with the nuclear pore. Nup153 depletion leads to the TREX-2 subunits’ relocation from the nuclear pore to the nucleoplasm. The depletion of TPR leads to PCID2 relocation to the nucleoplasm and Xmas-2 retention at the nuclear pore and does not affect ENY2 redistribution. The TREX-2 subunits form several contacts with Nup153 and TPR. Hence, both nucleoporins are involved in the interaction with TREX-2 and TREX-2-dependent export in Drosophila.