赭纤虫RNA聚合酶Ⅰ基因片段的分析

ANALYSIS OF THE GENE FRAGMENT ENCODING RNA POLYMERASE Ⅰ FROM BLEPHRISMA

赭纤虫被认为是一类进化过程中较为原始的纤毛虫。本研究以储纤虫基因组DNA为模板，利用锚定PCR技术，扩增出RNA聚合酶I第二大亚基基因片段，并对扩增出的基因片段进行了克隆和序列分析。结果表明：由该基因片段导出的氨基酸序列中共有10个半胱氨酸，均由通用密码子UGU、UGC编码，开放读框中不存在由UGA转译为半眈氨酸这一非通用密码的现象。

Blepharisma is thought to be a relatively primitive genus in the phylum Ciliophora.In this study, two DNA fragments of the second largest subunits of the RNA polymerase I were amplified from the genomic DNA of Blepharisma japonicum using anchorPCR procedure. The fragments were cloned and sequenced. The polypeptide deduced from the fragments consists of 463 amino acids and contains 10 cysteines which were all encoded by the common cystiene codons, UGU and UGC. There is no UGA codon in the open reading frame.