The cDNA encoding the luciferase from lantern mRNA of one diurnal firefly Pyrocoelia pygidialis Pic, 1926 has been cloned, sequenced and functionally expressed. The cDNA sequence of P pygidialis luciferase is 1647 base pairs in length, coding a protein of 548 amino acid residues. Sequence analysis of the deduced amino acid sequence showed that this luciferase had 97.8% resemblance to luciferases from the fireflies Lampyris noctiluca, Lampyris turkestanicus and Nyctophila cf. caucasica. Phylogenetic analysis using deduced amino acid sequence showed that P pygidialis located at the base of Lampyris＋Nyctophila clade with robust support （BP=97%）; but did not show a monophyletic relationship with its congeneric species P pectoralis, P tufa and P miyako, all three are strong luminous and nocturnal species. The expression worked in recombinant Escherichia coli. Expression product had a 70kDa band and emitted yellow-green luminescence in the presence of luciferin. Five loops in the P pygidialis luciferase, L1 （NI98-G208）, L2 （T240-G247）, L3 （G317-K322）, L4 （L343-I350） and L5 （G522-D532）, were found from the structure modeling analysis in the cleft, where it was considered the active site for the substrate compound entering and binding. Different amino acid residues between the luciferases of P. pygidialis and the three other known strong luminous species can not explain the situation of weak or strong luminescence. Future study of these loops, residues or crystal structure analysis may be helpful in understanding the real differences between the luciferases between diurnal and nocturnal species.
为了比较不同地域萤火虫荧光素酶基因的进化关系,通过GenBank中已知的荧光素酶基因保守区段设计引物,利用5′-RACE(rapid-amplification of cDNAends)和3′-RACE技术克隆了来自云南省文山州和西双版纳州的同种卵黄萤荧光素酶基因cDNA和全基因序列.来自不同地域的2种卵黄萤荧光素酶在基因序列上存在3个不同碱基位点,但是它们编码的荧光素酶只存在1个不同的氨基酸.卵黄萤荧光素酶基因全长(从起始密码子到终止密码子)1998bp,包含7个外显子,6个内含子,其cDNA序列共1976bp,包含102bp5′UTR(untranslated region)、1635bp的荧光素酶基因开放阅读框和239bp的3′UTR序列.卵黄萤荧光素酶基因的开放阅读框编码1个544个氨基酸的蛋白质,比同属的其它几种荧光素酶少4个氨基酸.来自2个不同地域的卵黄萤荧光素酶在进化上是比较保守的,它们与北美萤火虫Photinus pyralis荧光素酶在碱基序列上分别有62.9%和63%相似性.
目的克隆和分析荧光素再生酶基因(LRE)。方法通过GeneBank中已知的荧光素再生酶基因保守区段设计引物,利用5’RACE(rapid-amplification of cDNA ends)和3’RACE技术克隆了来自云南省西双版纳州的卵黄萤(Luciola ovalis)荧光素再生酶基因cDNA和全基因序列。通过GeneBank、National Center for Biotechnology Information和ProDom at the ExPASy Server软件和数据库进行序列分析。结果卵黄萤荧光素再生酶的cDNA序列和基因序列存在2个不同碱基位点,但是它们编码的荧光素再生酶是相同的。卵黄萤荧光素再生酶基因全长(从起始密码子到终止密码子)为1131bp,包含5个外显子4个内含子,其cDNA序列为1008bp,包含924bp的荧光素酶基因开放阅读框和84bp的3’UTR序列。卵黄萤荧光素酶基因的开放阅读框编码1个307个氨基酸的蛋白质。它与北美萤火虫(Photinus pyralis)荧光素再生酶在碱基序列和氨基酸序列上分别有61.8%和53.3%的相似性。结论成功地克隆了荧光素再生酶的cDNA和基因序列,为其在基因工程中的应用奠定了基础。
