Related Experiment Video
Updated: Sep 13, 2025
11:40
Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy
Published on: June 25, 2013
12.2K
Structural basis for the evolution of a domesticated group II intron-like reverse transcriptase to function in host
Seung Kuk Park1, Mo Guo1, Jennifer L Stamos1
1Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712.
Summary
Bacterial reverse transcriptase (RT) evolved for DNA repair. Structural studies reveal unique adaptations in G2L4 RT that optimize its function in double-strand break repair (DSBR) via microhomology-mediated end-joining (MMEJ).
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Bacterial group II intron-like reverse transcriptase (G2L4 RT) previously shown to function in double-strand break repair (DSBR).
- Mobile group II intron-encoded RTs possess basal DSBR activity utilizing conserved non-long terminal repeat (non-LTR)-retroelement RT structural features.
Purpose of the Study:
- Determine the structural basis of G2L4 RT function in DSBR.
- Elucidate unique structural adaptations optimizing G2L4 RT for microhomology-mediated end-joining (MMEJ).
Main Methods:
- X-ray crystallography to determine G2L4 RT apoenzyme structure.
- X-ray crystallography to determine G2L4 RT snap-back DNA synthesis structure.
Main Results:
- Identified an RT3a structure stabilizing the apoenzyme in an inactive state.
- Revealed a longer N-terminal extension/RT0-loop and modified active site favoring strand annealing.
- Discovered a conserved dimer interface for G2L4 RT homodimer localization and MMEJ positioning.
Conclusions:
- G2L4 RT possesses unique structural adaptations for DSBR via MMEJ.
- Understanding these structures provides insights into RT function in DNA repair.
- Findings suggest strategies for optimizing RTs in genome engineering.
More Related Videos
07:55Detection of Homologous Recombination Intermediates via Proximity Ligation and Quantitative PCR in Saccharomyces cerevisiae
Published on: September 11, 2022
1.9K
09:31Amplification, Next-generation Sequencing, and Genomic DNA Mapping of Retroviral Integration Sites
Published on: March 22, 2016
17.8K
Related Concept Videos
03:08LTR Retrotransposons
17.9K
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
17.9K
02:31Homologous Recombination
52.2K
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
52.2K
02:33Retroviruses
12.7K
Retroviruses and retrotransposons both insert copies of their genetic elements into the genome of the host cell. Thus, the viral genes are passed on when the host genome is replicated or translated. A typical retroviral DNA sequence contains 3-4 genes that encode the different proteins required for its structural assembly and function as a molecular parasite. This DNA is transcribed into a single mRNA, which is very similar in structure to conventional mRNAs, i.e., it is capped at the 5’...
12.7K
02:32Exon Recombination
3.7K
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon...
Exon shuffling follows “splice frame rules.” Each exon...
3.7K
02:10Translesion DNA Polymerases
10.2K
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...
10.2K
01:10Retrovirus Life Cycles
46.9K
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the...
46.9K