Tsugeki R, Olson M L, Fedoroff N V
Biotechnology Institute, The Pennsylvania State University, University Park, USA.
Gravit Space Biol Bull. 1998 May;11(2):79-87.
The maize Ac-Ds transposable element family has been used as the basis of transposon mutagenesis systems that function in a variety of plants, including Arabidopsis. We have developed modified transposons and methods which simplify the detection, cloning and analysis of insertion mutations. We have identified and are analyzing two plant lines in which genes expressed either in the root cap cells or in the quiescent cells, cortex/endodermal initial cells and columella cells of the root cap have been tagged with a transposon carrying a reporter gene. A gene expressed in root cap cells tagged with an enhancer-trap Ds was isolated and its corresponding EST cDNA was identified. Nucleotide and deduced amino acid sequences of the gene show no significant similarity to other genes in the database. Genetic ablation experiments have been done by fusing a root cap-specific promoter to the diphtheria toxin A-chain gene and introducing the fusion construct into Arabidopsis plants. We find that in addition to eliminating gravitropism, root cap ablation inhibits elongation of roots by lowering root meristematic activities.
玉米Ac-Ds转座因子家族已被用作转座子诱变系统的基础，该系统在包括拟南芥在内的多种植物中发挥作用。我们开发了改良的转座子和方法，简化了插入突变的检测、克隆和分析。我们已经鉴定并正在分析两个植物株系，其中在根冠细胞或根冠静止细胞、皮层/内皮层原始细胞和柱细胞中表达的基因已被携带报告基因的转座子标记。分离出了一个用增强子捕获Ds标记的根冠细胞中表达的基因，并鉴定了其相应的EST cDNA。该基因的核苷酸和推导的氨基酸序列与数据库中的其他基因没有显著相似性。通过将根冠特异性启动子与白喉毒素A链基因融合，并将融合构建体导入拟南芥植物中，进行了基因消融实验。我们发现，除了消除向重力性外，根冠消融还通过降低根分生组织活性来抑制根的伸长。
