Investigation of Wza in Erythromycin Sensitivity of Escherichia coli K30 E69 by Genetic Complementation

07/13/2017

Brian Yuen, Jerome Ting, Kevin Kang, Timothy Wong​

Volume 21
Fall 2016 / Winter 2017

Escherichia coli K30 strains express group 1 capsule that is polymerized and transported by the Wzy-dependent pathway. This involves proteins encoded by genes wza, wzb, and wzc. Previous studies have found that deletions of wza and wzc from the erythromycin sensitive K30 wild-type strain results in a change to an erythromycin resistant phenotype. It is unknown why the deletions of wza and wzc confers resistance to erythromycin. In this study, we attempted to complement a wza deletion mutant with a plasmid encoded copy of wza. We first reproduced the previously reported erythromycin sensitive phenotype of the wild-type K30 strain E69 and the resistant phenotype of the wza mutant strain CWG281 on plates. We then constructed a plasmid encoding the wza coding sequence with a 200 base pair putative regulatory region upstream of the methionine translational start site. Complementation of CWG281 with our wza plasmid construct did not result in reversion to an erythromycin sensitive phenotype. Further investigation to evaluate Wza protein expression level in the wza complemented strain is required to
validate the requirement of Wza in erythromycin sensitivity.