Question

Select all that apply. Artificial transformation of E. coli DH5alpha with which of the following plasmids will likely enable growth on Minimal media containing lactose as the sole carbon source and supplemented with ampicillin?

1. pUC18

2 .pHSG298

3. pUC18 with lacZ cloned into the MCS

4. pHSG298 with lacZ cloned into the MCS

Answer 1

pHSG298 plasmid (has kanamycin resistant gene) has a lacZ gene cloned into the MCS however, it lacks an ampicillin resistant gene and therefore, the transformants with the plasmid will fail o grow on minimal media containing lactose and ampicillin as they would be sensitive to the antibiotic.Therefore, option 2 and 4 are incorrect.

In case of pUC18, the plasmid vector has an ampicillin resistant gene, thus it can tolerate growing and surviving on medium containing ampicillin. It also has a lacZ gene promoter int he MCS and also a lacZ marker. also, as DH5 alpha strains are utilized,cells are defined by three mutations recA1, endA1 which help plasmid insertion and lacZM15 which enable blue white screening. Therefore, option (1) and (3) are correct as artificial transformation with these would enable growh on minimal media containing lactose as carbon source and ampicillin as antibiotic.