# The −10 region adjacent to open reading frames is a common expression pattern in Deinococcus-Thermus

## TL;DR

This study shows that a specific DNA region called the −10 motif is commonly used to start gene expression in the Deinococcus-Thermus phylum, often without a long RNA leader.

## Contribution

The study identifies the −10 motif as a key promoter region for leaderless mRNA in the Deinococcus-Thermus phylum.

## Key findings

- The −10 motif functions as a promoter for leaderless gene transcription in Deinococcus radiodurans.
- The −10 motif is commonly found upstream of ORFs in the Deinococcus-Thermus phylum.
- Adding a −35 region can enhance transcription levels in this system.

## Abstract

This study reveals that the promoter −10 region adjacent to open reading frames for gene expression via leaderless mRNA constitutes an important mode of gene expression in the Deinococcus-Thermus phylum.

Gene transcription and translation are fundamental processes that underpin the vitality of living organisms. In bacteria, the classic promoter elements for transcription include the −35 region and the −10 region, whereas the ribosome binding site (RBS) is essential for translation. Our investigation of the upstream sequences of ORFs in Deinococcus radiodurans has confirmed a −10 region-like motif, which appears as 5′-TANNNT-3′ (−10-motif). Through rigorous experimental validation, we have established that this −10-motif functions as the classical −10 region of the promoter during transcription, responsible for initiating transcription of leaderless genes (mRNA products that do not have or only have a very short 5′-UTR), and exhibits specific spacing requirements relative to the ORF. Moreover, our findings suggest that sequences containing −10-motif can serve as promoters for D. radiodurans and introduction of the −35 region at appropriate positions can significantly enhance transcription levels. Genomic analysis revealed that the −10-motif located a few base pairs (bp) upstream of ORFs is common within the Deinococcus-Thermus (D-T) phylum (also known as Deinococcota) and responsible for the transcriptional initiation of leaderless genes. Given these insights, we propose that the −10 region adjacent to the ORF for gene expression via leaderless mRNA constitutes an important mode of expression in the D-T phylum, which may contribute to the extraordinary environmental adaptability observed in this group of microorganisms.