Abstract
Although assimilation of inorganic nitrogen is a critical biochemical process for plant growth, the underlying regulatory mechanism has remained to be resolved. Here, we investigated a transcription factor (TF) that contributes to expression of nitrogen assimilation genes in the primitive red alga Cyanidioschyzon merolae.
DNA microarray and Northern blot analyses showed that expression of MYB-1 encoding an R2R3-type MYB TF was significantly increased under nitrogen deprivation condition (-N). Accumulation of MYB-1 protein and its nuclear localization were also observed in response to the -N. Furthermore, chromatin immunoprecipitation analysis with anti-MYB-1 antibody and gel-mobility shift assay using C. merolae crude extract containing nuclear proteins demonstrated that MYB-1 specifically binds to promoter regions of nitrogen assimilation genes, NRT, NIR, and GS under the -N. These results clearly suggested that MYB-1 controls nitrogen assimilation-related gene expression as a positive regulator in response to nitrogen status.
