Our Stellar Competent 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. This E. coli HST08 strain provides high transformation efficiency and since these cells lack the gene cluster for cutting foreign methylated DNA (mrr-hsdRMS-mcrBC and mcrA), they are very 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 lacZ alpha gene.

Our Stellar Competent Cells (dam−/dcm−) are generated from 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, so for transformation, it is highly recommended to use this product for constructing plasmids as mentioned above. Stellar Competent Cells are ideal for use with our In-Fusion HD Cloning Plus products.