Bacteria can recognize and produce a human protein from a human gene because the fundamental processes of gene expression—transcription (DNA to mRNA) and translation (mRNA to protein)—are conserved across life forms. The bacterial cellular machinery can read the human DNA sequence (if it is inserted properly in bacterial cells) and transcribe it into mRNA. Then, bacterial ribosomes translate this mRNA into protein. Key points include:
- The genetic code is universal, meaning bacteria and humans use the same codon sequences to specify amino acids in proteins, allowing bacteria to produce human proteins.
- For successful expression, the human gene is often inserted into bacteria with bacterial promoter sequences so the bacteria can properly initiate transcription.
- While some processes differ—such as bacteria not naturally performing RNA splicing—human genes used in bacteria for protein production are usually modified or synthesized as cDNA without introns.
- Human proteins can sometimes be secreted by bacteria if the signal peptides are compatible, as these peptides directing protein localization have conserved features.
- This technology is widely used in biotechnology to produce human proteins like insulin in bacteria.
Overall, bacteria can produce human proteins because the core molecular mechanisms of reading genes and synthesizing proteins are shared and compatible across species.
