Shen Huaishun, Cao Kaiming, Wang Xiping
State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, PR China.
BMB Rep. 2008 Feb 29;41(2):132-8. doi: 10.5483/bmbrep.2008.41.2.132.
AtbZIP16 and AtbZIP68 are two putative G group bZIP transcription factors in Arabidopsis thaliana, the other three members of G group bZIPs are GBF1-3 which can bind G-box. Members of G group have conservative protein structure: highly homological basic region and a proline-rich domain in the N-terminal region. Here, we report that AtbZIP16 and AtbZIP68 could bind cis elements with ACGT core, such as G-box, Hex, C-box and As-1, but with different binding affinities which from high to low were G-box > Hex > C-box > As-1; AtbZIP16 and AtbZIP68 could form homodimer and form heterodimer with other members of G group; N-terminal proline rich domain of AtbZIP16 had transactivation activity in yeast cells while that of AtbZIP68 did not; AtbZIP16 and AtbZIP68 GFP fusion protein localized in the nucleus of onion epidermal cells. These results indicated that AtbZIP16 and AtbZIP68 were two new members of GBFs. In Arabidopsis, AtbZIP16 and AtbZIP68 may also participate in light-responsive process in which GBF1-3 are involved.
AtbZIP16和AtbZIP68是拟南芥中两个假定的G组成员bZIP转录因子，G组bZIP的其他三个成员是能结合G盒的GBF1-3。G组成员具有保守的蛋白质结构：高度同源的碱性区域以及N端富含脯氨酸的结构域。在此，我们报道AtbZIP16和AtbZIP68能结合具有ACGT核心的顺式元件，如G盒、Hex、C盒和As-1，但结合亲和力不同，从高到低依次为G盒>Hex>C盒>As-1；AtbZIP16和AtbZIP68能形成同二聚体，并与G组的其他成员形成异二聚体；AtbZIP16的N端富含脯氨酸的结构域在酵母细胞中具有反式激活活性，而AtbZIP68的没有；AtbZIP16和AtbZIP68的绿色荧光蛋白融合蛋白定位于洋葱表皮细胞的细胞核中。这些结果表明AtbZIP16和AtbZIP68是GBF的两个新成员。在拟南芥中，AtbZIP16和AtbZIP68可能也参与了GBF1-3所涉及的光响应过程。
