Figure 2From: Novel reference genes for quantifying transcriptional responses of Escherichia coli to protein overexpression by quantitative PCRDistribution of the expression levels of genes examined in E. Coli BL21 (DE3). Box plot representation of the expression levels of seventeen candidate reference genes and two commonly used house-keeping genes among the 72 biological samples. The expression level of each gene was represented as the absolute copy number per unit input total RNA (0.0625 μg), quantified by qPCR using serial dilutions of standards. Primer design, assay efficiency and intra- and inter-assay variations were reported in supplementary data (Additional file 1: supplementary table 1).Back to article page