Related Experiment Video
Updated: Feb 22, 2026
11:04
Author Spotlight: Methods for Electroporation and Transformation Confirmation in Limosilactobacillus reuteri DSM20016
Published on: June 23, 2023
5.1K
Bacillus subtilis RecA with DprA-SsbA antagonizes RecX function during natural transformation
Shimin Le1,2, Ester Serrano3, Ryo Kawamura1,2
1Department of Physics, National University of Singapore, 117551, Singapore.
Nucleic Acids Research
|September 16, 2017
Summary
Bacillus subtilis transformation relies on RecA protein regulation. DprA-SsbA and RecX proteins form a new network, with DprA-SsbA antagonizing RecX to enable RecA filament formation for efficient transformation.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- RecA protein is essential for DNA repair and recombination.
- Bacillus subtilis transformation efficiency is influenced by regulatory proteins like DprA and RecX.
- Understanding the interplay between RecA, DprA, RecX, and single-stranded DNA binding proteins (SsbA, SsbB) is key to elucidating transformation mechanisms.
Purpose of the Study:
- To investigate the regulatory roles of Bacillus subtilis DprA and RecX proteins in RecA-mediated DNA transformation.
- To elucidate the mechanism by which DprA-SsbA and RecX modulate RecA filament dynamics on single-stranded DNA.
- To understand how these interactions influence chromosomal and plasmid transformation efficiency.
Main Methods:
- In vitro biochemical assays to study protein-DNA interactions.
- Analysis of RecA filament formation and dynamics in the presence of RecX, DprA, SsbA, and SsbB.
- Competition assays for binding to single-stranded DNA.
- DNA strand exchange assays.
Main Results:
- RecA·ATP binding could not displace RecX, SsbA, or SsbB from single-stranded DNA, while RecA·dATP showed partial displacement.
- RecX promoted reversible depolymerization of RecA·ATP filaments.
- The DprA-SsbA complex reversed RecX-mediated inhibition of RecA filament extension.
- RecX inhibited DNA strand exchange when added before RecA, but this inhibition was reversed when RecX was added after RecA.
- RecA nucleation was more sensitive to RecX than filament growth.
Conclusions:
- DprA-SsbA facilitates the formation of active RecA filaments, directly counteracting RecX inhibition.
- RecX and DprA alter RecA filament dynamics, which is crucial for chromosomal transformation.
- DprA-SsbA and RecX represent a novel regulatory network controlling RecA function during natural transformation in Bacillus subtilis.
Related Concept Videos
02:53Conservative Site-specific Recombination and Phase Variation
6.9K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
6.9K
01:21Repressible Operon: trp Operon
2.0K
The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...
2.0K