What are the steps in the process of bacterial transformation?
Posted February 23, 2024
Answer
Key steps in the process of bacterial transformation include:
- Preparation of competent cells: Bacteria are treated to become competent, allowing them to take up DNA. This can be done through electroporation, heat shock treatment, or the use of certain chemicals.
- Binding of DNA to the cell surface: Double-stranded DNA released from lysed cells binds to cell surface receptors non-covalently. DNA sequence-specific recognition is not required, allowing organisms to potentially incorporate DNA from outside their species.
- Processing and uptake of free DNA (usually in a 3’ to 5’ direction): Membrane-bound endonucleases nick and cleave the bound double-stranded DNA into smaller fragments, enabling the single strands to enter the cell through a DNA translocation channel that spans the membrane.
- Integration of the DNA into the chromosome by recombination: On integrating into the chromosome, the transformed DNA replaces the chromosomal DNA fragment by recombination. Considerable nucleotide sequence homology between the fragment in the chromosome and the donating DNA fragment is necessary for integration. In the case of plasmids, the plasmid with the donor DNA is inserted during heat shock or electroporation. The cells with plasmid can be grown in a growth media supplemented with a specific antibiotic to enable detection.
Additional resources
Impact of heat shock step on bacterial transformation efficiency