衣藻质体分裂相关基因CrFtsZ2的克隆及其进化分析

ＦｔｓＺ(ｆｉｌａｍｅｎｔｉｎｇｔｅｍｐｅｒａｔｕｒｅｓｅｎｓｉｔｉｖｅ)是一类从大肠杆菌温度敏感型突变体中分离到的基因 .该基因与Ｅ .ｃｏｌｉ细胞分裂密切相关 .突变体由于细胞分裂受阻而呈现“长丝状”1] .此类基因于 1980年首次被克隆2 ] .随后的研究表明 ,ＦｔｓＺ蛋白在Ｅ .ｃｏｌｉ分裂细胞的凹陷处形成环状多聚体 ,Ｚ环 ,是Ｅ .ｃｏｌｉ细胞分裂的限制因子3 ] .衣藻属于绿藻 ,在现存的所有单细胞真核藻类中 ,绿藻是与陆生植物亲缘关系最近的一支4] .由于衣藻为单细胞真核生物 ,并且仅含有一个巨大的叶绿体 ,因而是研究…

Cloning and Phylogenetic Analysis of cDNA Fragment CrFtsZ 2 of Plastid Division Gene in Chlamydomonas reinhardtii

It is generally accepted that chloroplast was originated from a photosynthetic cyanobacterium by endosymbiosis. Recent findings indicated that a FtsZ like protein, which was the homologue of the essential prokaryotic cell division protein, involved in the division of chloroplasts in plants. Using degenerate oligodeoxyribonucleotide primers based on conserved regions of the prokaryotic cell division protein FtsZ, a 570?bp cDNA fragment, named CrFtsZ 2, was isolated from Chlamydomonas reinhardtii by RT PCR. It was used to search the Chlamydomonas reinhardtii EST Database, and several contig EST sequences were found. The complete CrFtsZ 2 cDNA sequence was assembled by software and was amplified by RT PCR. With a 1?305?bp ORF(opening reading frame), the full length 1?815?bp CrFts Z cDNA had a 19?bp 5′UTR and a 490?bp 3′UTR. The CrFtsZ 2, which showed significant homology with other FtsZs , was a typical FtsZ gene, and encoded a precursor of 434 amino acid residues with a putative transit peptide in its N terminal. Phylogenetic tree of 23 FtsZs homologies reconstructed based on 300 conserved amino acid regions of the FtsZs suggested that CrFtsZ2 shared an ancestor probably with the FtsZ in cyanobacteria.