Standard Cloning Vector pUC18

pUC18 is a small, high copy cloning vector for replication in E. coli. It has been constructed using the ampicillin resistance gene and the pMB1 origin of replication from pBR322. The pMB1 of pUC18 differs from the pBR322 origin by a single point mutation and the lack of the rop gene, leading to a high copy number. pUC18 has a multiple cloning site within the lacZ alpha-fragment. Inserts cloned into this site disrupt beta -galactosidase activity and give rise to white colonies on X-Gal/IPTG plates. Foreign DNA inserted in-frame with the lacZ gene will be expressed as a fusion protein (containing a portion of the beta-galactosidase) under control of the lac promoter. The promoter is inducible with IPTG and followed by an initiation codon as well as a ribosome binding site. pUC18 differs from pUC19 in the multiple cloning site orientation.