Deleting the hns Gene for the H-NS Protein in Escherichia coli Reduces the Transformation Efficiency Following the Heath Shock Transformation Protocol

One commonly used, yet little understood method for transferring DNA into cells is the temperature shock transformation method (TST) that exposes competent bacteria to o o successive temperatures (4 C and 42 C). This study tested the effect of the gene for the heatstable nucleoid structuring protein (H-NS) on the efficiency of the TST method in an effort to find a way to improve the transformation efficiency of a cell. H-NS is a cold shock protein (CSP) that has demonstrated preferential binding of horizontally acquired genes. A comparison of the transformation efficiency of the parental strain and the hns knockout suggested that the hns gene is involved during TST and that the absence of the gene decreased the transformation efficiency of the cell. The absence of the hns gene affected the phenotype of individual colonies as well as the ability of cells to recover from cold temperature incubations.