Intragenic DNA inversions expand bacterial coding capacity 2024 Bhatt et al

[Andy]

Abstract

Bacterial populations that originate from a single bacterium are not strictly clonal and often contain subgroups with distinct phenotypes1. Bacteria can generate heterogeneity through phase variation—a preprogrammed, reversible mechanism that alters gene expression levels across a population1. One well-studied type of phase variation involves enzyme-mediated inversion of specific regions of genomic DNA2. Frequently, these DNA inversions flip the orientation of promoters, turning transcription of adjacent coding regions on or off2. Through this mechanism, inversion can affect fitness, survival or group dynamics3,4.

Here, we describe the development of PhaVa, a computational tool that identifies DNA inversions using long-read datasets. We also identify 372 ‘intragenic invertons’, a novel class of DNA inversions found entirely within genes, in genomes of bacterial and archaeal isolates. Intragenic invertons allow a gene to encode two or more versions of a protein by flipping a DNA sequence within the coding region, thereby increasing coding capacity without increasing genome size. We validate ten intragenic invertons in the gut commensal Bacteroides thetaiotaomicron, and experimentally characterize an intragenic inverton in the thiamine biosynthesis gene thiC.

Paywall, https://www.nature.com/articles/s41586-024-07970-4

 

[Andy]

Bacteria Flip Gene Segments to Alter Proteins Surprisingly Often, with Implications for Human Health

"Proteins are vital to our bodies. They serve as structural building blocks for our tissues and organs and are responsible for their functioning in both health and disease. Genes, like recipes, contain instructions for making proteins. Usually, each essential protein is produced from a single gene. Now, new research shows that some bacteria can actually produce two or more proteins from a single gene by “flipping” underlying stretches of DNA.

While scientists have long known that DNA inversions can occur in bacteria, this study is the first to describe these inversions, or “invertons,” within individual genes. What’s more, the findings, from research supported by NIH and reported in the journal Nature , suggest that this flipping happens more often than scientists suspected.

The findings, from Ami S. Bhatt at Stanford Medical School in Stanford, CA, and her colleagues, may have important implications, not only for bacteria, but also for human health. For example, bacteria’s ability to flip genes and alter proteins on their surfaces may restrict the ability of our immune systems to recognize and effectively respond to infectious microbes. Invertons also likely play roles in how our microbiomes, the communities of microorganisms that live in and on us, develop and change within our bodies. Our microbiomes influence our metabolisms, immune responses, and more."

More at https://directorsblog.nih.gov/2024/...gly-often-with-implications-for-human-health/