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.