This is a promoter cloning plasmid vector using expression of tetracycline resistance for selection. (ATCC staff) This was constructed by inserting an oligonucleotide containing an EcoRI site into the HindIII site of pBR316, inactivating the tet promoter. It is resistant to low levels of tetracycline without an insert and can be used to clone only strong promoters. [2] Medium is 1227 LB plus ampicillin. Hosts: E.coli RR1, E.coli.