Abstract
We have described the lip19 subfamily of basic region-leucine zipper protein (bZIP)-encoding genes from plants. In Arabidopsis, there are 75 bZIP-encoding genes (AtbZIP1-AtbZIP75) which, based on criteria of associated common domains, have been subdivided into 10 groups designated A to I and S. Here, we characterized the three group S members, AtbZIP2, AtbZIP11, and AtbZIP53, showing high sequence similarity to lip19 subfamily. Those gene products were localized to the nucleus and showed strong DNA binding activity to hexamer and C/G box hybrid sequences. Also, transactivation activity was examined in yeast and plant cells. The expression of the genes upon exposure to various abiotic stresses and to hormone treatments was examined in Arabidopsis. We found that AtbZIP11 and AtbZIP53 were responsive to cytokinin and high salt stress, respectively. To fully understanding the regulatory roles of AtbZIP11 and AtbZIP53 in gene transcription, we have commenced detailed analyses of AtbZIP11- and AtbZIP53-overexpressing plants.
