Rv3787c Influences Growth Dynamics of Mycobacterium tuberculosis

Abstract

Simple Summary Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, remains one of the world’s deadliest infectious diseases. Identifying which bacterial genes aid survival and transmission could reveal new therapeutic targets. In this study, we studied Rv3787c, which belongs to a family of genes encoding enzymes involved in modifying other internal bacterial molecules. Previous research identified a variation in this gene within M. tuberculosis strains that spread easily among humans, suggesting that Rv3787c helps the bacterium interact with the host. Bacteria lacking the Rv3787c gene grew normally under most stress conditions and produced surface fatty molecules comparable to those of wild-type bacteria. However, after enduring prolonged oxygen deprivation—a condition mimicking the host environment—the mutant bacteria resumed growth faster than normal strains once oxygen returned. We also detected these mutant bacteria slightly earlier when infecting human immune cells, although they survived and multiplied inside these cells as effectively as normal bacteria. Overall, our results demonstrate that Rv3787c is not essential for intracellular survival, but it may delay the bacterium’s ability to restart growth after stressful conditions. This suggests the gene acts as a kind of “brake” on bacterial growth under specific circumstances.