Schrumpfová Petra Procházková, Vychodilová Ivona, Dvořáčková Martina, Majerská Jana, Dokládal Ladislav, Schořová Sárka, Fajkus Jiří
Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, CZ, 62500, Czech Republic; Functional Genomics and Proteomics, CEITEC National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, Brno, CZ, 62500, Czech Republic.
Plant J. 2014 Mar;77(5):770-81. doi: 10.1111/tpj.12428. Epub 2014 Feb 18.
Although telomere-binding proteins constitute an essential part of telomeres, in vivo data indicating the existence of a structure similar to mammalian shelterin complex in plants are limited. Partial characterization of a number of candidate proteins has not identified true components of plant shelterin or elucidated their functional mechanisms. Telomere repeat binding (TRB) proteins from Arabidopsis thaliana bind plant telomeric repeats through a Myb domain of the telobox type in vitro, and have been shown to interact with POT1b (Protection of telomeres 1). Here we demonstrate co-localization of TRB1 protein with telomeres in situ using fluorescence microscopy, as well as in vivo interaction using chromatin immunoprecipitation. Classification of the TRB1 protein as a component of plant telomeres is further confirmed by the observation of shortening of telomeres in knockout mutants of the trb1 gene. Moreover, TRB proteins physically interact with plant telomerase catalytic subunits. These findings integrate TRB proteins into the telomeric interactome of A. thaliana.
尽管端粒结合蛋白是端粒的重要组成部分，但在植物中，表明存在类似于哺乳动物端粒保护蛋白复合体结构的体内数据有限。对一些候选蛋白的部分特性分析尚未鉴定出植物端粒保护蛋白的真正组成成分，也未阐明其功能机制。拟南芥的端粒重复序列结合（TRB）蛋白在体外通过端粒盒类型的Myb结构域与植物端粒重复序列结合，并且已证明其与POT1b（端粒保护蛋白1）相互作用。在这里，我们使用荧光显微镜证明了TRB1蛋白与端粒在原位共定位，以及使用染色质免疫沉淀证明了其在体内的相互作用。通过观察trb1基因敲除突变体中端粒的缩短，进一步证实了TRB1蛋白作为植物端粒组成成分的分类。此外，TRB蛋白与植物端粒酶催化亚基发生物理相互作用。这些发现将TRB蛋白整合到了拟南芥的端粒相互作用组中。
