影响鼻疽伯克霍尔德氏菌基因组密码子用法的因素分析

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Journal of Genetics and Genomics (Formerly Acta Genetica Sinica) April 2007,34(4):362—372 Available online at www.sciencedirect.com ,, 鬻学 ScienceDi rect 

The Factors Shaping Synonymous Codon Usage in the Ge-- 

Sheng Zhao 一,Qin Zhang 一,Zhihua Chen ,Yixin Zhao ,Jincheng Zhong '① 

1.College ofLife Science and Technology,Southwest UniversityforNationalities Chengdu 610041,China; 2.Jingmen Technical ofCollege,Jingmen 448000,China 

Abstract:Burkholderia mallei is regarded as a potential biological weapon by the Centers for Disease Control and Prevention.In this study,the main factors shaping codon usage in the genome ofB.mallei ATCC 23344 were firstly reported.The results showed that the primary trend in codon usage variation in the B.mallei is due to translational selection;while compositional mutation bias is relatively the weakerinfluence and the hydrophobicity ofeach protein and gene length are only the minor influences.At the salrle time 21 codons defined firstly as‘optimal codons’might provide more useful information for the expression of target genes and development of a vaccine to prevent glanders. Keywords:Burkholderia malle ATCC 23344;codon usage;correspondence analysis 

When molecular sequence data started to accu— 

mulate nearly 20 years ago.it was noted that DNA 

sequences that code for proteins did not randomly choose among codons that specify the same amino acid.Indeed the observation of departing from uni— 

form codon usage for each amino acid was a common feature 功ese observed patterns in synonymous 

codon usage were not simple and varied among genes within a genome,and among genomes.So codon us— 

age has not been easy to provide a satisfactory expla— nation for the particular pattern that is found in a given genome.In unicellular organisms,such as Es— 

cherichia coli,Bacillus subtilis,Saccharomyces cere- visiae,and Dictyrostelium discoideum,the codon us- 

age is attributable to the equilibrium between natural selection and compositional mutation bias|11.1’Ilis paradigm has been successfully applied to several 

multicellular eukaryotes, such as Drosophila ,,lelanogas r【 and Caenorhabditis elegans【3J.How— ever,in certain prokaryotes with extremely high A+T Or G+C cOntents[ 】and in human[ ,mutation bias is 

the major factor accounting for the variation in codon usage.Analysis of codon usage pauems reveal the 

information about the molecular evolution of indi— 

vidual genes and can provide data to train methods 

(genome—specific gene recognition algorithms)that detect protein coding regions in uncharacterized ge— 

nomic DNA. Glanders is one of the oldest diseases known and 

was first described by Aristotle.Burkholderia mallei, the causative agent of glanders,is a gram—negative 

bacillus and a host-adapted pathogen that does not persist in nature outside of its equine host.功ere have 

been no naturMly occurring cases of glanders in North 

America in the past 60 years,but laboratory workers 

are still at risk of infection with B malle via cutane- OUS and inhalational routes.Human glanders has been 

described as a painful and loathsome disease from 

Received:2006——06— 29;Accepted:2006— 10— 18 ①Corresponding author.E-mail:zhongjincheng518@sohu.com;Tel:+86—28—8552 2528,Fax:+86—28—8552 2799 

、^n『v、^f.jgenetgenomics.or

g 维普资讯 http://www.cqvip.com Sheng Zhao et a1.:The Factors Shaping Synonymous Codon Usage in the Genome ofBurkhoMeria mallei 363 

which few recover without antibiotic intervention 

There is little known about the virulence factors of this organism,but a recent report indicates that the capsular polysaccharide is essential for virulence in hamsters and miceI6】.At present.no effective vaccines are available against this organism,and information on the effective treatment of infections due to this 

organism with antibiotic therapy is sparse.最mallei 

has come under renewed scientific investigation as a result of recent concerns about biological weapons of 

mass destruction.As a Centers for Disease Control 

and Prevention category B agent,B.mallei is re- garded as a potential biological weapon because it is highly infectious as an aerosol and results in a disease 

that is painful,incapacitating,difficult to diagnose, and often fatal[71. Codon usage in B.mallei has not been investi. gated in any detail,and it is not clear how(or even it3 different genes should vary.Currently,the complete 

sequence of the B.mallei ATCC 23344 genome has been determined.Therefore,it is of interest to under- 

stand the factors that shape codon usage in this spe- 

cies.In this study,the analysis of codon usage bias in the mallei genome is reported using methods of 

multivariate statistical analysis and correlation analy-