Pandey Shashank K, Kim Jungmook
a Department of Bioenergy Science and Technology , Chonnam National University , Gwangju , Korea.
Plant Signal Behav. 2018 Jan 2;13(1):e1411450. doi: 10.1080/15592324.2017.1411450. Epub 2017 Dec 21.
The LATERAL ORGAN BOUNDARIES (LOB) DOMAIN (LBD) gene family members encode a class of plant-specific transcription factors that play important roles in many different aspects of plant growth and development. The LBD proteins contain a conserved LOB domain harboring a Leu zipper-like coiled-coil motif, which has been predicted to mediate protein-protein interactions among the LBD family members. Dimerization of transcription factors is crucial for the modulation of their DNA-binding affinity, specificity, and diversity, contributing to the transcriptional regulation of distinct cellular and biological responses. Our various molecular and biochemical experiments with genetic approaches on LBD16 and LBD18, which are known to control lateral root development in Arabidopsis, demonstrated that the conserved Leu or Val residues in the coiled-coil motifs of these transcription factors are critical for their dimerization as well as the transcriptional regulation to display their biological functions during lateral root formation. We further showed that beside the coiled-coil motif, the carboxyl-terminal region in LBD18 acts as an additional dimerization domain. These findings provide a molecular framework for the homo- and hetero-dimerization of the LBD family proteins for displaying their distinct and diverse biological functions in plants.
侧生器官边界（LOB）结构域（LBD）基因家族成员编码一类植物特有的转录因子，这些转录因子在植物生长发育的许多不同方面发挥着重要作用。LBD蛋白含有一个保守的LOB结构域，该结构域带有一个类似亮氨酸拉链的卷曲螺旋基序，据预测该基序可介导LBD家族成员之间的蛋白质-蛋白质相互作用。转录因子的二聚化对于调节其DNA结合亲和力、特异性和多样性至关重要，有助于对不同细胞和生物学反应进行转录调控。我们运用遗传学方法对拟南芥中已知控制侧根发育的LBD16和LBD18进行了各种分子和生化实验，结果表明这些转录因子卷曲螺旋基序中的保守亮氨酸或缬氨酸残基对于它们的二聚化以及在侧根形成过程中发挥生物学功能的转录调控至关重要。我们进一步表明，除卷曲螺旋基序外，LBD18的羧基末端区域还作为一个额外的二聚化结构域。这些发现为LBD家族蛋白的同二聚化和异二聚化提供了一个分子框架，以便它们在植物中发挥独特多样的生物学功能。
