The SE1 strain is recommended for protein expression when using StabyExpress, CherryExpress, StabyCodon or CherryCodon kits. This strain was derived from E. coli BL21(DE3) strain. SE1 is an expression strain allowing for the use of the T7 expression system. The gene encoding the T7 RNA polymerase is inserted into the chromosome of the expression bacteria. The protein expression is repressed by lacI and induced by the addition of IPTG into the culture medium or using an auto-inducible medium as Staby^TMSwitch. Additionaly, the SE1 bacteria contain the ccdB selection gene in its chromosome allowing for the perfect plasmid stabilization (even without antibiotics) and consequently higher yields of expressed proteins. For more information about the Staby^TM technology, please click here.

The genotype of the SE1 strain is: F-, CmR, ompT, lon, hsdSB (restriction-, modification-), gal, dcm, DE3 (lacI, T7polymerase under the control of the PlacUV5 promoter), ccdB+.

SE1 bacteria are available either as electro- or chemically- competent cells. Bacteria are shipped (in dry ice) with SOC medium. Each tube of SE1 electro-competent cells contains 50ul of competent bacteria . Each tube of SE1 chemically-competent cells contains 100ul of comptetent bacteria.(Other forms of packaging are available on request).