Phenotypic expression in E. coli of a DNA sequence coding for mouse dihydrofolate reductase.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Bacterial plasmids are crucial tools for genetic manipulation.
• Expressing mammalian genes in prokaryotic systems presents unique challenges.
• Dihydrofolate reductase is a key enzyme in folate metabolism.

Purpose of the Study:

• To construct and analyze bacterial plasmids capable of expressing mammalian genetic sequences.
• To investigate the phenotypic consequences of expressing mouse dihydrofolate reductase in bacteria.
• To assess the potential of such engineered plasmids for conferring drug resistance.

Main Methods:

• Construction of recombinant bacterial plasmids containing the mouse dihydrofolate reductase gene.
• Transformation of bacterial host cells with the engineered plasmids.
• Phenotypic analysis of transformed cells, including enzymatic assays and drug resistance testing.
• Characterization of the expressed protein for enzymatic activity, immunological reactivity, and molecular size.

Main Results:

• Successfully created bacterial plasmids expressing a mammalian genetic sequence.
• The expressed protein exhibited enzymatic properties, immunological reactivity, and molecular size consistent with mouse dihydrofolate reductase.
• Host bacterial cells containing the plasmids demonstrated resistance to the antimetabolic drug trimethoprim.

Conclusions:

• Bacterial plasmids can be engineered to contain and express functional mammalian genes.
• Expression of mouse dihydrofolate reductase in bacteria confers resistance to trimethoprim.
• This demonstrates a viable system for studying mammalian gene function and developing novel biotechnological applications.