Nup107 is a crucial regulator of torso-mediated metamorphic transition in <i>Drosophila melanogaster</i>.

Abstract

Nuclear pore complexes (NPCs), composed of nucleoporins (Nups), affect nucleocytoplasmic transport, thus influencing cell division and gene regulation. Nup107 subcomplex members have been studied in housekeeping functions, diseases, and developmental disorders. We report a unique regulatory function for Nup107 in metamorphic transition during <i>Drosophila</i> development. RNA interference (RNAi)-mediated <i>Nup107</i>-depleted larvae were arrested in the third-instar larval stage with no signs of pupariation. This lack of pupariation is primarily due to inhibited nuclear translocation and transcriptional activation by EcR. We demonstrate the involvement of Nup107 in the transcription of the <i>Halloween</i> genes, modulating ecdysone biosynthesis and the EcR pathway activation. The regulation of EcR-mediated metamorphosis by the receptor tyrosine kinase, <i>torso</i>, is well documented. Accordingly, overexpression of the <i>torso</i> and MAP-kinase pathway activator, <i>ras^V12</i>, in the <i>Nup107</i> depletion background rescues the phenotypes, implying that Nup107 is an epistatic regulator of Torso-mediated activation of EcR signaling during metamorphosis.