Nuclear pore complexes (NPCs), which comprise multiple copies of nucleoporins (Nups), are large protein assemblies embedded in the nuclear envelope connecting the nucleus and cytoplasm. Although it has been known that Nups affect flowering in Arabidopsis, the underlying mechanisms are poorly understood. Here, we show that loss of function of Nucleoporin 160 (Nup160) leads to increased abundance of CONSTANS (CO) protein and the resulting upregulation of FLOWERING LOCUS T (FT) specifically in the morning. We demonstrate that Nup160 regulates CO protein stability through affecting NPC localization of an E3-ubiquitin ligase, HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES1 (HOS1), which destabilizes CO protein in the morning period. Taken together, these results provide a mechanistic understanding of Nup function in the transition from vegetative to reproductive growth, suggesting that deposition of HOS1 at NPCs by Nup160 is essential for preventing precocious flowering in response to photoperiod in Arabidopsis.

核孔复合物 (NPC) 包含多个拷贝的核孔蛋白 (Nups)，是嵌入连接细胞核和细胞质的核膜中的大型蛋白质组装体。尽管已知 Nup 会影响拟南芥的开花，但其潜在机制仍知之甚少。在这里，我们表明核孔蛋白 160 ( Nup160 )的功能丧失导致 CONSTANS (CO) 蛋白丰度增加以及由此产生的FLOWERING LOCUS T ( FT)上调) 特别是在早上。我们证明 Nup160 通过影响 E3-泛素连接酶的 NPC 定位，渗透性响应基因 1 (HOS1) 的高表达来调节 CO 蛋白的稳定性，该酶在早晨破坏 CO 蛋白的稳定性。总之，这些结果提供了对从营养生长到生殖生长过渡过程中 Nup 功能的机制理解，表明 Nup160 在 NPCs 上的 HOS1 沉积对于防止拟南芥响应光周期的早熟开花是必不可少的。