Wageningen University and Research Centre, Bioscience, Droevendaalsesteeg 1, Wageningen 6708 PB, The Netherlands.
Vegetable Breeding and Genome Research Division, NARO Institute of Vegetable and Tea Science (NIVTS), 360 Kusawa, Ano, Tsu, Mie 514-2392, Japan.
Development. 2015 Feb 1;142(3):454-64. doi: 10.1242/dev.117168. Epub 2015 Jan 6.
Aintegumenta-like (AIL) transcription factors are key regulators of cell proliferation and meristem identity. Although AIL functions have been well described, the direct signalling components of this pathway are largely unknown. We show that baby boom (BBM) and other AIL proteins physically interact with multiple members of the L1-expressed homeodomain glabrous (HDG) transcription factor family, including HDG1, HDG11 and HDG12. Overexpression of HDG1, HDG11 and HDG12 restricts growth due to root and shoot meristem arrest, which is associated with reduced expression of genes involved in meristem development and cell proliferation pathways, whereas downregulation of multiple HDG genes promotes cell overproliferation. These results suggest a role for HDG proteins in promoting cell differentiation. We also reveal a transcriptional network in which BBM and HDG1 regulate several common target genes, and where BBM/AIL and HDG regulate the expression of each other. Taken together, these results suggest opposite roles for AIL and HDG proteins, with AILs promoting cell proliferation and HDGs stimulating cell differentiation, and that these functions are mediated at both the protein-protein interaction and transcriptional level.
无被膜蛋白（AIL）转录因子是细胞增殖和分生组织身份的关键调节剂。尽管 AIL 功能已得到很好的描述，但该途径的直接信号成分在很大程度上尚不清楚。我们表明，婴儿潮（BBM）和其他 AIL 蛋白与多个 L1 表达同源域光滑（HDG）转录因子家族成员物理相互作用，包括 HDG1、HDG11 和 HDG12。HDG1、HDG11 和 HDG12 的过表达由于根和芽分生组织的阻滞而限制了生长，这与参与分生组织发育和细胞增殖途径的基因的表达减少有关，而多个 HDG 基因的下调则促进了细胞过度增殖。这些结果表明 HDG 蛋白在促进细胞分化中起作用。我们还揭示了一个转录网络，其中 BBM 和 HDG1 调节几个常见的靶基因，并且 BBM/AIL 和 HDG 调节彼此的表达。总之，这些结果表明 AIL 和 HDG 蛋白的作用相反，AIL 促进细胞增殖，HDG 刺激细胞分化，这些功能在蛋白质-蛋白质相互作用和转录水平上都得到了介导。
