Won Su-Kyung, Lee Yong-Ju, Lee Ha-Yeon, Heo Yoon-Kyung, Cho Misuk, Cho Hyung-Taeg
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea.
Plant Physiol. 2009 Jul;150(3):1459-73. doi: 10.1104/pp.109.140905. Epub 2009 May 15.
Understanding the cellular differentiation of multicellular organisms requires the characterization of genes whose expression is modulated in a cell type-specific manner. The Arabidopsis (Arabidopsis thaliana) root hair cell is one model for studying cellular differentiation. In this study, root hair cell-specific genes were screened by a series of in silico and experimental filtration procedures. This process included genome-wide screening for genes with a root hair-specific cis-element in their promoters, filtering root-specific genes from the root hair-specific cis-element-containing genes, further filtering of genes that were suppressed in root hair-defective plant lines, and experimental confirmation by promoter assay. These procedures revealed 19 root hair-specific genes, including many protein kinases and cell wall-related genes, most of which have not been characterized thus far. Functional analyses of these root hair-specific genes with loss-of-function mutants and overexpressing transformants revealed that they play roles in hair growth and morphogenesis. This study demonstrates that a defined cis-element can serve as a filter to screen certain cell type-specific genes and implicates many new root hair-specific genes in root hair development.
了解多细胞生物的细胞分化需要对那些以细胞类型特异性方式调节表达的基因进行表征。拟南芥根毛细胞是研究细胞分化的一个模型。在本研究中，通过一系列计算机模拟和实验筛选程序对根毛细胞特异性基因进行了筛选。这个过程包括全基因组筛选启动子中具有根毛特异性顺式元件的基因，从含根毛特异性顺式元件的基因中筛选根特异性基因，进一步筛选在根毛缺陷型植株系中被抑制的基因，并通过启动子分析进行实验验证。这些程序揭示了19个根毛特异性基因，包括许多蛋白激酶和细胞壁相关基因，其中大多数迄今尚未得到表征。对这些根毛特异性基因进行功能缺失突变体和过表达转化体的功能分析表明，它们在毛发生长和形态发生中发挥作用。本研究表明，一个确定的顺式元件可以作为筛选某些细胞类型特异性基因的过滤器，并揭示了许多新的根毛特异性基因在根毛发育中的作用。
