一組由美國(guó),、韓國(guó)和法國(guó)的科學(xué)家組成的研究小組最近完成了對(duì)兩種實(shí)驗(yàn)室常用的大腸桿菌(E. coli)菌株基因組的測(cè)序工作,。這項(xiàng)研究發(fā)表在10月17日J(rèn)ournal of Molecular Biology雜志上,。
E. coli常與一些食源性疾病有關(guān)，但從人體腸道內(nèi)分離出來(lái)的兩種命名為K-12和B的良性大腸桿菌菌株卻是兩種重要實(shí)驗(yàn)用菌株,。大腸桿菌K-12的基因組的測(cè)序工作已于1997年完成,。而大腸桿菌B菌株自1918年被分離出來(lái)后，在1959年被分離為兩類實(shí)驗(yàn)用菌株：一類REL606用于研究長(zhǎng)期計(jì)劃作用,；另一類BL21(DE3)在醫(yī)學(xué)和工業(yè)上用于生產(chǎn)蛋白質(zhì),。因此，對(duì)這兩類B菌株的測(cè)序工作直到最近才完成,。
通過(guò)序列比較,，研究人員發(fā)現(xiàn)，K-12和B這兩種菌株基因序列的單個(gè)堿基對(duì)差異是非隨機(jī)分布的,。此外,，通過(guò)對(duì)比兩種不同的B菌株也發(fā)現(xiàn)了二者存在差異。（生物谷Bioon.com）
生物谷推薦原始出處：
Journal of Molecular Biology doi:10.1016/j.jmb.2009.09.052
Genome Sequences of Escherichia coli B strains REL606 and BL21(DE3)
Haeyoung Jeong1, Valérie Barbe2, Choong Hoon Lee1, 3, David Vallenet2, Dong Su Yu1, Sang-Haeng Choi1, Arnaud Couloux2, Seung-Won Lee1, Sung Ho Yoon1, Laurence Cattolico2, Cheol-Goo Hur1, 4, Hong-Seog Park1, 4, Béatrice Ségurens2, Sun Chang Kim3, Tae Kwang Oh1, 5, Richard E. Lenski6, F. William Studier7, , , Patrick Daegelen2, 8, , and Jihyun F. Kim1, 4, ,
1Korea Research Institute of Bioscience and Biotechnology (KRIBB), 111 Gwahangno, Yuseong, Daejeon 305-806, Korea
2CNRS UMR 8030, Genoscope (CEA), 2 rue Gaston Crémieux, CP 5706, 91000 Evry Cedex, France
3Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
4Functional Genomics Program, University of Science and Technology, Yuseong, Daejeon 305-333, Korea
521C Frontier Microbial Genomics and Applications Center, Yuseong, Daejeon 305-806, Korea
6Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
7Biology Department, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000, USA
8Inserm, 101 rue de Tolbiac, 75013 Paris, France
Escherichia coli K-12 and B have been the subjects of classical experiments from which much of our understanding of molecular genetics has emerged. We present here complete genome sequences of two E. coli B strains, REL606, used in a long-term evolution experiment, and BL21(DE3), widely used to express recombinant proteins. The two genomes differ in length by 72,304 bp and have 426 single base pair differences, a seemingly large difference for laboratory strains having a common ancestor within the last 67 years. Transpositions by IS1 and IS150 have occurred in both lineages. Integration of the DE3 prophage in BL21(DE3) apparently displaced a defective prophage in the λ attachment site of B. As might have been anticipated from the many genetic and biochemical experiments comparing B and K-12 over the years, the B genomes are similar in size and organization to the genome of E. coli K-12 MG1655 and have > 99% sequence identity over 92% of their genomes. E. coli B and K-12 differ considerably in distribution of IS elements and in location and composition of larger mobile elements. An unexpected difference is the absence of a large cluster of flagella genes in B, due to a 41 kbp IS1-mediated deletion. Gene clusters that specify the LPS core, O antigen, and restriction enzymes differ substantially, presumably because of horizontal transfer. Comparative analysis of 32 independently isolated E. coli and Shigella genomes, both commensals and pathogenic strains, identifies a minimal set of genes in common plus many strain-specific genes that constitute a large E. coli pan-genome.
