# Revelation of core promoter elements and bidirectional regulation of Geminivirus genes in Escherichia coli

## TL;DR

This study explores how geminiviruses regulate gene expression in bacteria and identifies key promoter elements involved in this process.

## Contribution

The study identifies a 36-bp bidirectional promoter core and cis-acting regulatory elements in geminivirus intergenic regions for cross-kingdom gene regulation.

## Key findings

- A 36-bp bidirectional promoter core was identified in the intergenic region of AYVV-NT.
- Cis-acting regulatory elements for C- and V-sense coding regions were characterized.
- Promoter activity varied across different E. coli strains, indicating strain-dependent regulation.

## Abstract

•The cross-kingdom gene expression ability of a geminivirus is studied in Escherichia coli.•Effects of different E. coli strains on promoter activities were revealed.•A 36-bp bidirectional promoter core was identified in the IR of AYVV-NT.•Cis-acting regulatory elements were identified for C- and V-sense coding regions.•Our results elucidated how geminiviruses may regulate gene expression in bacteria.

The cross-kingdom gene expression ability of a geminivirus is studied in Escherichia coli.

Effects of different E. coli strains on promoter activities were revealed.

A 36-bp bidirectional promoter core was identified in the IR of AYVV-NT.

Cis-acting regulatory elements were identified for C- and V-sense coding regions.

Our results elucidated how geminiviruses may regulate gene expression in bacteria.

Several geminiviruses have been show to possess cross-kingdom gene expression capability. In addition, the intergenic region (IR) of geminivirus genomes is known to regulate the transcription of viral early genes (complementary-sense, C-sense) and late genes (virion-sense, V-sense) located in opposite directions in viral genomic DNAs. However, the underlying mechanism remained elusive. In this study, the transcriptional regulation activities in the IR of ageratum yellow vein virus isolate NT (AYVV-NT), a monopartite geminivirus, were characterized in Escherichia coli, by using a promoter-trapping system. A functional bidirectional promoter core and regulatory elements for C- and V-sense genes were identified in the IR of AYVV-NT. Quantitative analyses revealed differences in promoter activity in various E. coli strains, suggesting that promoter regulation is strain-dependent and influenced by bacterial transcription factors. These findings provide insights into how plant-infecting geminiviruses may regulate gene expression in prokaryotic environments and highlight the potential applications of such viral regulatory elements in bacterial expression systems.

Image, graphical abstract