Complete Genome Sequence of Escherichia coli ER1821R, a Laboratory K-12 Derivative Engineered To Be Deficient in All Methylcytosine and Methyladenine Restriction Systems.

Michael G Jobling,Daniel N Frank,Elisabeth A Raleigh

doi:10.1128/genomea.00763-16

Michael G Jobling, Daniel N Frank + Show 1 more

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https://doi.org/10.1128/genomea.00763-16

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Abstract

Highlights

We present here the complete genomic sequence of a rifampin-resistant derivative of the Escherichia coli K-12 laboratory strain ER1821, engineered to be deficient in all known restriction systems, making it suitable for generating unbiased libraries from organisms with non-K-12 methylation patterns
ER1821 is derived from MM294 [7], from which the popular cloning strain DH1 (MM294 recA gyrA) was derived [8]
NC_017625.1) using the Geneious Read Mapper, produced a consensus sequence with 90-fold mean coverage, two large gaps corresponding to the e14 and immigration control region (ICR) deletions, and six discordant regions

Summary

Introduction

We present here the complete genomic sequence of a rifampin-resistant derivative of the Escherichia coli K-12 laboratory strain ER1821, engineered to be deficient in all known restriction systems, making it suitable for generating unbiased libraries from organisms with non-K-12 methylation patterns. Wild-type Escherichia coli strains restrict incoming DNA with foreign patterns of nucleotide modification [1, 2], reducing the recovery of gene libraries containing such modifications. E. coli K-12 derivative ER1821, engineered to be restriction deficient [3], has been useful for library preparation [4] and cloning DNA methyltransferases [5, 6]. The restriction systems were removed using P1 transduction to cure the e14 prophage encoding mcrA and delete the immigration control region (ICR) ⌬(mcrC-hsdmrr)114::IS10 [9].

Results

Conclusion