Related Experiment Video
Updated: Apr 10, 2026
07:59
Rapid and Specific Detection of Acinetobacter baumannii Infections Using a Recombinase Polymerase Amplification/Cas12a-based System
Published on: April 25, 2025
1.6K
Acinetobacter baumannii encodes multiple mutagenically and biochemically active DNA polymerase V variants
Debika Ojha1, Malgorzata Jaszczur1, Phuong Pham1
1Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, United States.
Nucleic Acids Research
|April 9, 2026
Summary
Acinetobacter baumannii possesses multiple DNA polymerase V variants that cause mutations in E. coli. Mutagenesis requires RecA and specific polymerase components, highlighting complex DNA repair mechanisms.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Acinetobacter baumannii harbors multiple umuDC homologs, encoding diverse DNA polymerase V (pol V) variants.
- These homologs suggest complex roles in DNA repair and mutagenesis within A. baumannii.
Purpose of the Study:
- To investigate the mutagenic potential of A. baumannii pol V variants in E. coli.
- To characterize the assembly and activity of A. baumannii pol V mutasomes.
Main Methods:
- Expression of A. baumannii umuDC homologs in E. coli.
- In vitro assembly and DNA synthesis assays of mutasome complexes.
- Analysis of translesion DNA synthesis (TLS) at thymine-thymine cyclobutane dimers.
Main Results:
- Six of twelve A. baumannii pol V variants exhibited mutagenic activity in E. coli, dependent on RecA.
- Five active pol VAb variants formed stable mutasome complexes (UmuD'2CAb-RecAAb-ATP/ATPγS).
- One mutasome required an A. baumannii-encoded β/τ clamp; TLS showed variant-specific misincorporation at T^T dimers.
Conclusions:
- A. baumannii pol V variants contribute to mutagenesis, with specific variants and RecA being essential.
- Mutasome complex formation and accessory factors like the β/τ clamp influence polymerase activity.
- RecA's conserved role in mutagenesis is further supported by a specific mutation abolishing A. baumannii pol V activity.
Related Concept Videos
02:10Translesion DNA Polymerases
11.9K
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
11.9K
01:31Proofreading
9.9K
Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase...
Errors During Replication are Corrected by the DNA Polymerase...
9.9K
01:43Proofreading
62.4K
Overview
62.4K
00:43Bacterial RNA Polymerase
33.9K
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
33.9K
03:01The Replisome
39.8K
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with...
39.8K
01:28Inhibitors of Bacterial DNA Synthesis
67
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These...
67