Gonzalo Lucia, Gagliardi Delfina, Zlauvinen Camila, Gulanicz Tomasz, Arce Agustín L, Fernandez Josefina, Cambiagno Damian A, Merchante Catharina, Zienkiewicz Agnieszka, Jarmolowski Artur, Manavella Pablo A
Instituto de Agrobiotecnología del Litoral, CONICET, Universidad Nacional del Litoral, 3000, Santa Fe, Argentina.
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM "La Mayora"), Universidad de Málaga-Consejo Superior de Investigaciones Cientificas (UMA-CSIC), 29010, Málaga, Spain.
Nucleic Acids Res. 2025 Sep 5;53(17). doi: 10.1093/nar/gkaf885.
The regulation of miRNA biogenesis and movement is essential for plant development and environmental responses. HASTY (HST), a karyopherin protein, has been implicated in miRNA biogenesis and movement, though its role in non-cell-autonomous miRNA movement remains unclear. Through a genetic screen, we identified that mutations in the HAWAIIAN SKIRT (HWS) gene suppress the developmental defects of hst mutants by restoring miRNA movement. Our findings show that HWS interacts with nuclear transport factors and nuclear pore complex (NPC) components, including NUP1, positioning HWS as a regulator of miRNA nuclear export. Using microscopy and fluorescence in situ hybridization, we showed that pri-miRNA transcription, and likely their co-transcriptional processing, occur at the nuclear pore. Notably, we uncovered an antagonistic relationship between HST and HWS in regulating MIRNA transcription at the NPC and AGO1 loading, which could explain the observed changes in miRNA movement. HST promotes the association of MIRNA loci with the NPC, spatially positioning co-transcriptional processing by the NPC. Conversely, HWS negatively regulates this process by degrading MEDIATOR 37 subunits and detaching the processing complex from the NPC. Our data provide evidence of spatial coordination of miRNA transcription, biogenesis, and movement, highlighting a novel role for the NPC in the miRNA pathway.
微小RNA（miRNA）生物合成与转运的调控对于植物发育和环境响应至关重要。核转运蛋白HASTY（HST）参与了miRNA的生物合成与转运，但其在非细胞自主miRNA转运中的作用尚不清楚。通过遗传筛选，我们发现夏威夷裙边（HWS）基因的突变通过恢复miRNA转运来抑制hst突变体的发育缺陷。我们的研究结果表明，HWS与核转运因子及核孔复合体（NPC）组分相互作用，包括NUP1，这表明HWS是miRNA核输出的调节因子。利用显微镜和荧光原位杂交技术，我们发现初级miRNA（pri-miRNA）转录，可能还包括其共转录加工，都发生在核孔处。值得注意的是，我们发现HST和HWS在调控NPC处的miRNA转录及AGO1装载过程中存在拮抗关系，这可以解释观察到的miRNA转运变化。HST促进miRNA基因座与NPC的结合，在空间上定位NPC的共转录加工过程。相反，HWS通过降解中介体37亚基并使加工复合体从NPC上脱离来负向调节这一过程。我们的数据为miRNA转录、生物合成和转运的空间协调提供了证据，突显了NPC在miRNA通路中的新作用。
