UC San Diego

Inorganic nitrogen, in the form of nitrate, is both an important nutrient and signaling molecule in the growth and development of plants. The transcription factor NLP7, a downstream component of the nitrate signaling pathway, along with its homologue NLP6, were shown in this study to participate in DNA-protein interactions with an enhancer sequence from the Nitrate Reductase NIA1 gene in in vitro electrophoretic mobility shift assays. Furthermore, this study showed that two binding sites exist within the NIA1 enhancer element for NLP6 and NLP7. In vivo studies using the transient expression system in Nicotiana benthamiana showed that these factors could activate expression of a nitrate-responsive gene in a nitrate-dependent manner. Results from this study suggest that NLP6 and NLP7 regulate the transcription of target nitrate-responsive genes by directly binding to cis-acting elements in the promoter region