Restriction digests of the clone give the following sizes (kb): EcoRI--4.5; BamHI/EcoRI--4.2, 0.4; BglI--3.0, 1.2, 0.40. Inserts containing up to 350 bp upstream of the start codon can be trimmed with Bal31 after linearizing with an enzyme cutting upstream of the insert. Recircularize the vector to bring a start codon into juxtaposition with a strong ribosome-binding site. Because cI857 is expressed by the plasmid itself, from its natural promoter PM, the vector may be used in virtually any E. coli strain. The sequence surrounding the cloning sites has been used to design primers for direct sequencing, including the M13 universal primer. Expression vector containing a strong ribosome-binding site and primer sites useful for sequencing. Encodes cI857. Constructed by inserting a segment of pBR322 (nt 975 - nt 1338) between the HpaI site and a cluster of restriction sites. |
