【摘要】 从八肋游仆虫细胞中克隆到一种新的β-微管蛋白基因.序列分析结果表明:在大核中,该基因全长1561bp.与已经报道过的β-微管蛋白基因不同,它的5′端基因上游调控序列有49 bp,AT含量为75.5%.上游调控序列中仅有一个TATAA框,没有CCAAT框;该基因的3′端的下游调控序列有121 bp,富含AT碱基,达到86.8%,其中有明显的反向重复序列.上下游调控序列中各有一个断裂信号TTGAA和TTCAA,负责从小核到大核发育过程中大核染色体的形成.从小核基因组中克隆到相应的基因片段,比大核中的序列多7个碱基5′-CATGCTC-3′,其功能尚不清楚.序列比对表明,新的β-微管蛋白基因与已经报道的β-微管蛋白基因的同源性92.3%,阅读框中有2个氨基酸的变化,将它命名为β2-微管蛋白基因.更多还原

【Abstract】 A novel β-tubulin gene was cloned from the cell of Euplotes octocarinatus.The gene from macronuclear DNA was 1561 bp in length,including non-coding regions and telomeric sequences at both ends.Different from reported β-tubulin gene,5′non-coding regions was 49 bp in length,abundance in AT(75.5 %),containing a TATAA-box.3′-noncoding regions was 121 bp length,abundance in AT reaching to 86.8 %,containing two standard reverse repeat sequences.A break signal TTGAA and TTCAA appeared in 5′ and 3′ non-coding regions,17 bp away from initiate codon and stop codon,which were responsible for development of chromosome in macronucleus that formed from micronucleus through breakage process.The new β-tubulin gene cloned from micronuclear DNA had a additional small sequences 5′-CATGCTC-3′,which function was unclear.The result of BLAST in NCBI demonstrated that the new β-tubulin gene shared a homology of 92.3 % with reported β-tubulin gene.The new β-tubulin gene was named as β2-tubulin.更多还原