The Arabidopsis nucleoporins 98A/B are essential for NLP7 nuclear accumulation in response to nitrate

The nuclear compartment is an essential evolutionary gain in eukaryotes. Stimulus-induced nuclear accumulation of transcription factors allows rapid and reversible regulation of gene expression. Nitrate-regulated nuclear accumulation of the master transcriptional regulator NLP7, a member of the RWP-RK family of transcription factors, triggers a major gene expression cascade. Whether and how this process is regulated at the level of the nuclear pore remains elusive. Here we show that the mobile nucleoporin NUP98A and its close homolog NUP98B interact with NLP7 in the nucleus and that the nitrate-triggered nuclear accumulation of NLP7 is impaired in their absence. We also demonstrated that the simultaneous loss of NLP7 and NUP98A has a strong and specific effect on the expression of nitrate-regulated genes, resulting in a drastic reduction in plant growth. Our results indicate that plant NUP98 acts on nitrate use by plants through its interaction with the top-tier NLP7 transcription factor. Significance StatementNucleoporins (NUPs) are fundamental components of all eukaryotic cells. They are increasingly recognized not only as structural components of the nuclear pore complex but also as active regulators of gene expression and signaling pathways across eukaryotes. NUP98 proteins in mammals are multifunctional proteins with key roles beyond nucleocytoplasmic transport. The adaptation of plants to nitrogen availability is crucial for their development and yield. The master transcription factor NLP7 orchestrates early responses to nitrate supply and is regulated by a rapid nitrate-regulated nucleo-cytosolic shuttling. In this study, we demonstrate that the Arabidopsis nucleoporins 98A/B enable acclimation of Arabidopsis to N status by gating the nucleocytoplasmic trafficking of the nitrate sensor NLP7 transcription factor, enlarging their functional network. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=164 HEIGHT=200 SRC="FIGDIR/small/677877v2_ufig1.gif" ALT="Figure 1"> View larger version (73K): org.highwire.dtl.DTLVardef@1bae44corg.highwire.dtl.DTLVardef@e245bforg.highwire.dtl.DTLVardef@1513778org.highwire.dtl.DTLVardef@110cce2_HPS_FORMAT_FIGEXP M_FIG C_FIG