钝顶螺旋藻FtsZ在大肠杆菌中的表达和定位

FtsZ是与真核微管蛋白类似的原核骨架蛋白,能在细胞分裂位点聚合组装成环状结构而调控细胞分裂过程。为了研究钝顶螺旋藻（Spirulina platensis）FtsZ蛋白的功能,构建了钝顶螺旋藻FtsZ与绿色荧光蛋白GFP融合表达的质粒,并在大肠杆菌中进行了表达和定位研究,结果发现,表达融合蛋白GFP-FtsZ的大肠杆菌细胞由短杆状变为长丝状,且菌丝体长度与融合蛋白的表达量呈正比。在荧光显微镜下观察到融合蛋白GFP-FtsZ在长丝状体细菌中呈有规律的点状分布,这说明FtsZ蛋白功能高度保守,钝顶螺旋藻FtsZ蛋白能识别大肠杆菌分裂位点并装配成环状结构调控大肠杆菌细胞分裂,FtsZ蛋白的过量表达能抑制大肠杆菌正常的细胞分裂而导致长丝状体细胞的形成。

Expression and Localization of FtsZ from Spirulina platensis in Escherichia coil

Prokaryotic cytoskeletal protein FtsZ, a microtubule homolog, assembles into a compact circular structure at the mid-cell and plays an important rote in cytokinesis. To explore the function of FtsZ in Spirulina platensis morphogenesis, we cloned the ftsZ gene from S. platensis and constructed its fusion tag of GFP expression plasmid pGFP-FtsZ. The recombined expression vector was transformed to Escherichia coil B121. Western blot analysis showed that the GFP-FtsZ fusion gene was successfully expressed in the transformant. The transformed bac- teria that expressed the GFP-FtsZ protein changed from normal short-rod shapes and formed long filaments. The length of the filamentation cells was proportional to the expression amount of FtsZ in cells. Regular-dot distribution of the GFP-FtsZ fusion protein in transformed bacteria was observed by fluorescent light microscopy. The data demonstrated that FtsZ was a highly con- served functional protein. The FtsZ of S. platensis assembled the complete cytokinesis appara- tus and formed a Z-ring structure at the future division site to regulate cell division in E. coll. The overexpression of FtsZ blocked the normal cell cycle and led to cell filamentation.