番茄CONSTANS类似基因的克隆与表达分析

Molecular Cloning and Expression Analysis of a CONSTANS-like Gene SlCO1 from Solanum lycopersicum

以一个受生物钟调节的番茄转录衍生片段（transcription-drived fragment，TDF）为信息探针，通过在NCBI EST数据库中进行电子延伸和RT—PCR验证，获得了番茄CO类似基因的cDNA全长序列，命名为SlCO1（GenBank登录号，EU636698）。SlCO1蛋白含有386个氨基酸，氨基端存在两个B—box型锌指结构，羧基端含有一个TFC结构域。SlCO1蛋白与CO类蛋白的氨基酸一致性为34％-46％，但在B—box锌指和CCT结构域处高度保守。基因组序列包含1个535bp的内含子，位于B—box锌指和CCT结构域之间。表达谱分析表明，SlCO1在叶片中优势表达，在根和茎中表达较弱。SlCO1的克隆为了解CO类似基因在番茄开花中的作用奠定了基础。

Derived from tomato and influenced by circadian clock, a transcription-drived fragment （TDF） was used as a seed sequence for searching homologous ESTs through electronical elongation in NCBI database. A full-length CONSTANS-like gene designed as SlCO1 （GenBank accession number, EU636698 ） , is cloned using RT-PCR. The deduced SlCO1 protein consisting of 386 amino acid residues contains two B-box zinc finger motifs near the amino terminus and a conserved CCT domain near the carboxy terminus. Moreover, a 535 bp intron is located between the B-box and CCT domain. Although SlCO1 proteins shares 34% -46% identity with other CO proteins, the deduced amino acid sequence is highly conserved in the B-box and CCT domain. SlCO1 expresses specifically and strongly in leaf, but weakly in root and stem. Cloning of SlCO1 will provide a scientific basis for understanding the role of CONSTANS-likc genes in tomato flowering process.