A Single Amino-Acid Substitution at Lysine 40 of an Arabidopsis thaliana α-tubulin Causes

A Single Amino-Acid Substitution at Lysine 40 of an Arabidopsis thaliana α-tubulin Causes Extensive

Cell Proliferation and Expansion Defects

Xue Xiong;Deyang Xu;Zhongnan Yang;HaiHuang;Xiaofeng Cui

【期刊名称】《植物学报（英文版）》 【年(卷),期】2013(055)003

【摘要】Microtubules are highly dynamic cytoskeletal polymers of α/β-tubulin

heterodimers

that

undergo

multiple

post-translational

modifications essential for various cellular functions in eukaryotes.The lysine 40 (K40) is largely conserved in α-tubulins in many eukaryote species,and the post-translational modification by acetylation at K40 is critical for neuronal development in vertebrates.However,the biological function of K40 of α-tubulins in plants remains unexplored.In this study,we show in Arabidopsis thaliana that constitutive expression of mutated forms of α-tubulin6 (TUA6) at K40 (TUA6κ40A or TUA6κ40Q),in which K40 is replaced by alanine or glutamine,result in severely reduced plant size.Phenotypic characterization of the 35S:TUA6κ40A transgenic plants revealed that both cell proliferation and cell expansion were affected.Cytological and biochemical analyses showed that the accumulation ofα-and β-tubulin proteins was significantly reduced in the transgenic plants,and the cortical microtubule arrays were severely disrupted,indicating that K40 of the plant α-tubulin is critical in