Tuberculosis, a deadly infectious disease, faces a breakthrough as scientists uncover a flaw in the bacteria’s gene expression control model. Previously, it was believed that a protein called ‘σ factor’ initiated bacterial transcription by binding RNA polymerase, only to be released once RNA elongation began. This process, known as the ‘σ-cycle’, was thought to be universal among bacteria, including TB bacteria.
A recent study from Bose Institute, Kolkata, part of the Department of Science and Technology (DST), challenges this long-standing assumption. Researchers Dr. Jayanta Mukhopadhyay and Dr. N. Hazra discovered that while some σ factors in M. tuberculosis detach from RNA polymerase during transcription, others remain attached throughout the process.
Published in the Nucleic Acids Research journal, their findings reveal that the traditional concept of the “universal σ-cycle” in molecular biology textbooks does not hold true for all bacteria or regulatory proteins. Specifically focusing on Mycobacterium tuberculosis, the study highlights how different σ factors behave distinctly during transcription, shedding light on the initial phase of gene expression.
The study’s revelation that σF remains bound to RNA polymerase unveils a previously unknown mechanism by which the bacterium maintains the expression of stress-response genes. This insight carries significant implications for TB biology, especially in combating drug-resistant strains that pose a growing global threat to disease eradication. M. tuberculosis bacteria’s ability to regulate gene expression under severe stress conditions within the human host is crucial for its survival.
