Chemically Competent Cells—High Efficiency Competent Cells for Cloning
An E. coli HST08 strain that provides high transformation efficiency. These cells can be used in a wide variety of applications—from preparation of cDNA and genomic libraries, to construction of longer-length genomic libraries, subcloning, and even methylated DNA cloning. Stellar Competent Cells lack the gene cluster for cutting foreign methylated DNA (mrr-hsdRMS-mcrBC and mcrA), and are therefore useful for cloning methylated DNA. The cells can also be used for blue/white screening (i.e., alpha-complementation) when transformed with vectors containing the lacZalpha gene. Stellar Competent Cells are ideal for use with Clontech's In-Fusion Cloning Kits.
Stellar Competent Cells (dam–/dcm–)
An E. coli HST04 strain that lacks the genetic factors (dam and dcm) necessary for the methylation of DNA. Plasmids prepared using this product can be cut by restriction enzymes which are normally blocked by dam or dcm methylation. A dam/recA double mutation is lethal, so the parent strain is recA+. Therefore, it follows that transformation of extracellular DNA with repeat sequences can result in recombination by recA. This product is not a suitable cloning host. For transformation, it is highly recommended to use this product for constructing plasmids as mentioned above.