Hofr Ctirad, Sultesová Pavla, Zimmermann Michal, Mozgová Iva, Procházková Schrumpfová Petra, Wimmerová Michaela, Fajkus Jirí
Department of Functional Genomics and Proteomics, Institute of Experimental Biology, Faculty of Science, Masaryk University, CZ-62500 Brno, Czech Republic.
Biochem J. 2009 Apr 1;419(1):221-8, 2 p following 228. doi: 10.1042/BJ20082195.
Proteins that bind telomeric DNA modulate the structure of chromosome ends and control telomere function and maintenance. It has been shown that AtTRB (Arabidopsis thaliana telomere-repeat-binding factor) proteins from the SMH (single-Myb-histone) family selectively bind double-stranded telomeric DNA and interact with the telomeric protein AtPOT1b (A. thaliana protection of telomeres 1b), which is involved in telomere capping. In the present study, we performed the first quantitative DNA-binding study of this plant-specific family of proteins. Interactions of full-length proteins AtTRB1 and AtTRB3 with telomeric DNA were analysed by electrophoretic mobility-shift assay, fluorescence anisotropy and surface plasmon resonance to reveal their binding stoichiometry and kinetics. Kinetic analyses at different salt conditions enabled us to estimate the electrostatic component of binding and explain different affinities of the two proteins to telomeric DNA. On the basis of available data, a putative model explaining the binding stoichiometry and the protein arrangement on telomeric DNA is presented.
结合端粒DNA的蛋白质可调节染色体末端的结构，并控制端粒的功能与维持。研究表明，来自SMH（单Myb-组蛋白）家族的拟南芥端粒重复序列结合因子（AtTRB）蛋白可选择性结合双链端粒DNA，并与参与端粒封端作用的端粒蛋白AtPOT1b（拟南芥端粒保护蛋白1b）相互作用。在本研究中，我们首次对这个植物特异性蛋白家族进行了定量DNA结合研究。通过电泳迁移率变动分析、荧光偏振和表面等离子体共振分析全长蛋白AtTRB1和AtTRB3与端粒DNA的相互作用，以揭示它们的结合化学计量和动力学。在不同盐条件下的动力学分析使我们能够估算结合的静电成分，并解释这两种蛋白对端粒DNA的不同亲和力。基于现有数据提出了一个推测模型，用于解释结合化学计量和端粒DNA上的蛋白质排列。
