Genome Sequences of Escherichia coli B strains REL606 and BL21(DE3)
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- 作者：Haeyoung Jeong ; Valé ; rie Barbe ; Choong Hoon Lee ; David Vallenet ; Dong Su Yu ; Sang-Haeng Choi ; Arnaud Couloux ; Seung-Won Lee ; Sung Ho Yoon ; Laurence Cattolico ; Cheol-Goo Hur ; Hong-Seog Park ; Bé
- 关键词：E. coli B ; REL606 ; BL21(DE3) ; Comparative genomics ; Similarity of E. coli B and K-12
- 刊名：Journal of Molecular Biology
- 出版年：2009
- 出版时间：11 December 2009
- 年：2009
- 卷：394
- 期：4
- 页码：644-652
- 全文大小：368 K
文摘
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.