CCMB scientists develop genetic toolkit to shine light on TB’s inner workings

A powerful new genetic toolkit that could make it easier to study the bacteria responsible for Tuberculosis (TB), one of the world’s deadliest infectious diseases, has been developed by Vinay Kumar Nandicoori, Director of the CSIR-Centre for Cellular and Molecular Biology (CCMB).

Investigate how different proteins work together

Designed for use in mycobacteria, the new system could accelerate efforts to understand how the TB bacterium survives, grows and causes disease. It gives scientists tools to switch genes on, track proteins inside bacterial cells, and investigate how different proteins work together.

Despite decades of research, many genes in Mycobacterium tuberculosis, the bacterium that causes TB, remain poorly understood. Scientists typically rely on specially designed DNA molecules known as ‘shuttle vectors’ to introduce genes into bacterial cells and study their functions. However, the complex protein interactions within a cell are difficult to monitor.

New shuttle vectors with fluorescent markers

To address this challenge, Mr. Nandicoori’s research student Asis Kumar used existing knowledge to create a collection of 40 new shuttle vectors. These molecular delivery vehicles carry selected genes into bacterial cells, enabling researchers to study them in different ways.

The new genetic toolkit offers greater flexibility because the shuttle vectors can be equipped with fluorescent markers such as Green Fluorescent Protein (GFP) and ‘mCherry’, which make proteins glow under a microscope. This allows researchers to observe where specific proteins are located inside bacterial cells and how they move during growth and division, explained Mr. Nandicoori, in an exclusive interaction.

The team tested the new tools in Mycobacterium smegmatis, a harmless relative of the TB bacterium that is commonly used in laboratories. The fluorescent tags successfully highlighted the locations of key proteins involved in cell growth and division, confirming that the system worked as intended.

The toolkit also enables scientists to study several proteins simultaneously. The research team examined how four different regulatory proteins from the TB bacterium functioned within a single bacterial cell, providing insight into how proteins interact and coordinate critical cellular processes.

Another significant feature is a new purification method that reduces background contamination and improves the identification of proteins that naturally interact inside the cell. This is important because many biological processes are carried out not by individual proteins, but by groups of proteins working together, said the Director.

Mr. Nandicoori said the genetic toolkit could be expanded in the future with new genetic switches, protein tags and regulatory elements, making it adaptable to a wide range of experiments. The study was published in ‘Journal of Bacteriology’.