pBR322 is a commonly used cloning vector. When the gene for $\beta$-galactoside is inserted in the ampicillin resistance gene by using Pst I, the recombinant E.coli will lose ampicillin resistance due to insertional inactivation of the antibiotic resistance gene. The host (recombinant) cell will produce $\beta$-galactoside which is not a novel protein nor does it have dual ability. The transformed cells cannot resist ampicillin as they have lost ampicillin resistance. A recombinant E. coli is produced and the host cell will not undergo lysis due to insertion of $\beta$-galactoside gene.