title: Interacting TCP and NLP transcription factors control plant responses to nitrate availability.
abstract: Plants have evolved adaptive strategies that involve transcriptional networks to cope with and survive environmental challenges. Key transcriptional regulators that mediate responses to environmental fluctuations in nitrate have been identified; however, little is known about how these regulators interact to orchestrate nitrogen (N) responses and cell-cycle regulation. Here we report that teosinte branched1/cycloidea/proliferating cell factor1-20 (TCP20) and NIN-like protein (NLP) transcription factors NLP6 and NLP7, which act as activators of nitrate assimilatory genes, bind to adjacent sites in the upstream promoter region of the nitrate reductase gene,NIA1, and physically interact under continuous nitrate and N-starvation conditions. Regions of these proteins necessary for these interactions were found to include the type I/II Phox and Bem1p (PB1) domains of NLP6&7, a protein-interaction module conserved in animals for nutrient signaling, and the histidine- and glutamine-rich domain of TCP20, which is conserved across plant species. Under N starvation, TCP20-NLP6&7 heterodimers accumulate in the nucleus, and this coincides with TCP20 and NLP6&7-dependent up-regulation of nitrate assimilation and signaling genes and down-regulation of the G2/M cell-cycle marker gene,CYCB1;1TCP20 and NLP6&7 also support root meristem growth under N starvation. These findings provide insights into how plants coordinate responses to nitrate availability, linking nitrate assimilation and signaling with cell-cycle progression.
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Peizhu
authors.initials: P
authors.lastname: Guan
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Juan-José
authors.initials: JJ
authors.lastname: Ripoll
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Renhou
authors.initials: R
authors.lastname: Wang
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Lam
authors.initials: L
authors.lastname: Vuong
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093.
authors.forename: Lindsay J
authors.initials: LJ
authors.lastname: Bailey-Steinitz
authors.affiliation: Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701.
authors.forename: Dening
authors.initials: D
authors.lastname: Ye
authors.affiliation: Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093; ncrawford@ucsd.edu.
authors.forename: Nigel M
authors.initials: NM
authors.lastname: Crawford
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites; D019926:Cyclin B / Q000235:genetics / Q000378:metabolism; D059565:G2 Phase Cell Cycle Checkpoints; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; C462528:CycB1 protein, Arabidopsis; D019926:Cyclin B; C000626445:NIN-LIKE PROTEIN7, Arabidopsis; D009566:Nitrates; D020033:Protein Isoforms; C540502:TCP20 protein, Arabidopsis; D014157:Transcription Factors; C000620946:NIA1 protein, Arabidopsis; D050901:Nitrate Reductase
keywords: NIN-like protein; TCP; cell cycle; nitrate signaling; root growth