GO:0045950 negative regulation of mitotic recombination: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0045950 (negative regulation of mitotic recombination) describes any process that inhibits or decreases the rate of DNA recombination during mitosis.
• Mitotic recombination is suppressed by cell-cycle checkpoints and kinase signaling that restrain recombination machinery when sister chromatids are the preferred repair template.
• Key regulators include cell-cycle kinases such as CDK4, PLK1, and checkpoint kinases that phosphorylate recombination factors and limit their activity.
• Dysregulation of negative regulation of mitotic recombination can drive loss of heterozygosity and genome instability relevant to cancer and developmental disorders.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal testing of candidate negative regulators of mitotic recombination.
• EDITGENE provides end-to-end CRISPR cell model and library screening services to dissect negative regulation of mitotic recombination in disease contexts.
Description
GO:0045950, negative regulation of mitotic recombination, is a biological process ontology term defined as any process that inhibits or decreases the rate of DNA recombination during mitosis. Mitotic recombination is a form of homologous recombination that can occur between homologous chromosomes or sister chromatids during mitotic cell division, and its negative regulation is essential to preserve genome stability and prevent loss of heterozygosity. Understanding this process is critical because unscheduled or excessive mitotic recombination can lead to chromosomal rearrangements, oncogenic transformation, and therapy resistance in cancer. The QuickGO definition emphasizes inhibition or decrease of recombination rate specifically during mitosis, distinguishing it from meiotic recombination regulation. Research into negative regulation of mitotic recombination has revealed that cell-cycle kinases, phosphatases, and checkpoint proteins act as brakes on recombination machinery to ensure timely and accurate DNA repair. This article synthesizes authoritative QuickGO annotation and verified PubMed literature to provide a research-grade overview of the mechanisms, genes, disease links, and experimental models relevant to GO:0045950.
negative regulation of mitotic recombination At A Glance
| GO ID | GO:0045950 |
|---|---|
| GO term | negative regulation of mitotic recombination |
| Ontology | biological_process |
| Synonym | down regulation of mitotic recombination; down-regulation of mitotic recombination; downregulation of mitotic recombination; inhibition of mitotic recombination; negative regulation of recombination within rDNA repeats |
| Major function | Inhibits or decreases the rate of DNA recombination during mitosis to maintain genome stability |
| Related processes | Mitotic homologous recombination, DNA damage response, cell-cycle checkpoint control |
| Key regulators | Cell-cycle kinases (CDK4, PLK1), phosphatases (calcineurin), checkpoint proteins |
| Disease relevance | Cancer, loss of heterozygosity, genome instability syndromes |
What Is GO:0045950?
Negative regulation of mitotic recombination (GO:0045950) refers to any cellular process that inhibits or decreases the rate of DNA recombination during mitosis. This includes mechanisms that suppress homologous recombination between sister chromatids or homologous chromosomes, thereby preventing genomic rearrangements and loss of heterozygosity. The term encompasses regulation of recombination within ribosomal DNA repeats and other repetitive genomic regions.
Why Is negative regulation of mitotic recombination Important in Cell Biology?
Negative regulation of mitotic recombination is critical for maintaining genomic integrity because uncontrolled mitotic recombination can cause loss of heterozygosity, chromosomal rearrangements, and activation of oncogenes or loss of tumor suppressors. The process ensures that recombination-based DNA repair is deployed appropriately during mitosis, preventing inappropriate exchanges between repetitive sequences that could destabilize the genome. Dysregulation of this process is implicated in cancer predisposition, chemotherapy resistance, and developmental abnormalities, making it a key area for therapeutic target discovery.
• Prevents loss of heterozygosity and chromosomal rearrangements during mitosis.
• Maintains stability of repetitive genomic regions such as rDNA repeats.
• Coordinates DNA repair pathway choice with cell-cycle progression.
• Dysregulation contributes to cancer genome instability and tumor evolution.
• Modulates sensitivity to DNA-damaging chemotherapies and radiation.
• Provides targets for synthetic lethal strategies in cancers with recombination defects.
• Influences developmental processes by safeguarding progenitor cell genomes.
• Serves as a model for understanding conserved recombination control from yeast to humans.
What Happens During negative regulation of mitotic recombination?
Cell-cycle checkpoint enforcement
In simple terms: The cell checks its cycle stage and blocks recombination when it is not appropriate.
Negative regulation of mitotic recombination is tightly coupled to cell-cycle checkpoints that monitor DNA integrity and replication status. Polo-like kinase 1 (PLK1) and other checkpoint kinases phosphorylate recombination factors to restrain their activity until the appropriate cell-cycle phase. In Saccharomyces cerevisiae, S-phase cyclins negatively regulate G1 and G2 progression, indirectly limiting recombination during mitosis. This checkpoint enforcement ensures that recombination occurs only when sister chromatids are available as repair templates.
Phosphorylation-dependent inhibition of recombination factors
In simple terms: Adding phosphate groups to recombination proteins can switch them off.
Phosphorylation of recombination proteins by cell-cycle kinases such as CDK4 and PLK1 inhibits their pro-recombination activities. Calcineurin, a serine/threonine phosphatase, negatively regulates CDK4, thereby modulating cell-cycle progression and indirectly influencing recombination suppression. In meiotic contexts, Mek1-mediated phosphorylation of Rad54 inhibits recombination, illustrating a conserved phosphorylation-based brake mechanism that may have mitotic parallels. These post-translational modifications provide rapid and reversible control of recombination rate.
Suppression of recombination within repetitive DNA
In simple terms: The cell prevents dangerous exchanges between repetitive DNA sequences.
Negative regulation of mitotic recombination includes specific suppression of recombination within ribosomal DNA (rDNA) repeats and other repetitive elements. This prevents unequal crossing over and copy number variation that could disrupt essential genes. The QuickGO synonym 'negative regulation of recombination within rDNA repeats' highlights this specialized function. Mechanisms may involve chromatin structure, repeat-binding proteins, and checkpoint-mediated inhibition.
DMC1 and RAD51 attenuation
In simple terms: Specific recombination proteins are kept in check to avoid excessive strand exchange.
DMC1, a meiosis-specific recombinase, attenuates RAD51-mediated recombination in Arabidopsis, demonstrating that negative regulation can occur at the level of recombinase filament dynamics. While DMC1 is primarily meiotic, the principle that accessory factors can dampen RAD51 activity is relevant to mitotic recombination control. In mitotic cells, negative regulators may similarly limit RAD51 filament stability or turnover to prevent inappropriate recombination.
Telomere and spindle-associated regulation
In simple terms: Proteins at chromosome ends and the mitotic spindle help coordinate recombination suppression.
The telomeric protein Pin2/TRF1 is involved in regulating the mitotic spindle, linking telomere function to mitotic progression and potentially to recombination control. Proper spindle assembly and chromosome segregation reduce the likelihood of DNA damage that would trigger recombination. Thus, negative regulation of mitotic recombination is integrated with broader mitotic machinery.
Key Genes Involved in GO:0045950 negative regulation of mitotic recombination
The following genes and proteins have been experimentally implicated in negative regulation of mitotic recombination or related mitotic recombination control pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CDK4 | Cell-cycle kinase negatively regulated by calcineurin; influences G1/S progression and recombination timing | Target for cell-cycle and recombination studies |
| PLK1 | Polo-like kinase 1 regulates DNA damage response and checkpoint recovery, limiting recombination | Therapeutic target in cancers with recombination defects |
| RAD51 | Central recombinase; its activity is attenuated by negative regulators | Key node for recombination control |
| DMC1 | Meiotic recombinase that attenuates RAD51-mediated recombination | Model for recombinase attenuation |
| Mek1 | Kinase that phosphorylates Rad54 to inhibit recombination | Conserved brake mechanism |
| Rad54 | Recombination factor inhibited by Mek1 phosphorylation | Substrate for negative regulation |
| Wee1 | Kinase negatively regulated by nim1/cdr1; controls mitotic entry | Cell-cycle checkpoint component |
| nim1/cdr1 | Mitotic inducer that negatively regulates Wee1 | Upstream regulator of mitotic progression |
| Pin2/TRF1 | Telomeric protein involved in mitotic spindle regulation | Links telomere function to mitosis |
| S-phase cyclins | Negatively regulate G1 and G2 progression in yeast | Cell-cycle control of recombination |
| Rb1 | Deficiency induces synthetic lethality with ATR and PKMYT1 coinhibition | Cancer synthetic lethal target |
| ATR | DNA damage response kinase; coinhibition with PKMYT1 in Rb1-deficient cells | Therapeutic target in breast cancer |
| PKMYT1 | Membrane-associated tyrosine/threonine kinase; synthetic lethal with Rb1 deficiency | Drug target for combination therapy |
| Calcineurin | Serine/threonine phosphatase that negatively regulates CDK4 | Modulator of cell-cycle and recombination |
How Is negative regulation of mitotic recombination Regulated?
Negative regulation of mitotic recombination is controlled by cell-cycle checkpoint kinases (PLK1, ATR, PKMYT1) and phosphatases (calcineurin) that phosphorylate or dephosphorylate recombination factors. In yeast, S-phase cyclins negatively regulate G1 and G2 progression, indirectly suppressing recombination during mitosis. The Mek1 kinase phosphorylates Rad54 to inhibit recombination, providing a conserved phosphorylation-dependent brake. DMC1 attenuates RAD51-mediated recombination, illustrating regulation at the recombinase level. These regulatory layers ensure that recombination is suppressed when inappropriate, such as during G1 or when sister chromatids are not available.
negative regulation of mitotic recombination and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Rb1 | Breast cancer, synthetic lethality with ATR/PKMYT1 inhibition | Patient-derived xenografts, CRISPR KO cell lines |
| PLK1 | Cancer, DNA damage response dysregulation | Overexpression and point-mutation models |
| ATR | Cancer, replication stress response | Knockout and knock-in cell lines |
| PKMYT1 | Cancer, cell-cycle checkpoint | CRISPR KO and drug combination models |
| CDK4 | Cell-cycle dysregulation, cancer | Point-mutation and overexpression models |
Cancer and loss of heterozygosity
Dysregulation of negative regulation of mitotic recombination can lead to loss of heterozygosity and chromosomal rearrangements that drive cancer. Rb1 deficiency creates synthetic lethality with ATR and PKMYT1 coinhibition in breast cancer cell lines and patient-derived xenografts, linking cell-cycle and recombination control to therapeutic vulnerability. PLK1, a key regulator of the DNA damage response, is overexpressed in many cancers and is a target for inhibitors that modulate recombination.
Genome instability syndromes
Defects in suppressing mitotic recombination can cause genome instability syndromes characterized by chromosomal breaks and rearrangements. The suppression of recombination within rDNA repeats is particularly important because repeat instability is associated with aging and cancer. Loss of checkpoint control, as seen with Wee1 dysregulation, can lead to inappropriate mitotic entry and recombination.
Therapeutic implications
Targeting negative regulators of mitotic recombination, such as PLK1, ATR, and PKMYT1, is a promising strategy for synthetic lethal therapy in cancers with specific genetic defects. Understanding how these regulators function can guide combination therapies with DNA-damaging agents.
From negative regulation of mitotic recombination-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a candidate gene increase mitotic recombination? | CRISPR knockout cell line |
| Does a specific phosphorylation site regulate recombination suppression? | Point-mutation knock-in (phospho-dead/phospho-mimetic) |
| Does overexpression of a negative regulator reduce recombination? | Overexpression cell model |
| Where does the protein localize during mitosis? | Tagged knock-in (e.g., GFP) |
| Which genes synthetically interact with Rb1 deficiency? | CRISPR library screening |
| How does a mutation affect DNA repair pathway choice? | Knock-in reporter cell line |
How to Study the negative regulation of mitotic recombination Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR KO + reporter assay | Mitotic recombination rate | Causal gene testing |
| Phosphoproteomics | Phosphorylation of recombination factors | Identify regulatory sites |
| Live-cell imaging | Protein localization and foci dynamics | Spindle and recombination visualization |
| Synthetic lethal screen | Genetic interactions | Cancer target discovery |
| Western blot | Protein expression and modification | Validate KO/overexpression |
| Flow cytometry | Cell-cycle profile | Checkpoint analysis |
| Yeast genetics | Recombination frequency | Conserved mechanism studies |
CRISPR knockout and point-mutation models
CRISPR knockout of candidate negative regulators (e.g., PLK1, CDK4) followed by recombination reporter assays can test causality. Point mutations at phosphorylation sites (e.g., Rad54) can dissect phospho-dependent regulation.
Recombination reporter assays
Direct repeat GFP or luciferase reporters can quantify mitotic recombination rates in cells with CRISPR edits. These assays measure homologous recombination between repeated sequences.
Proteomics and phosphoproteomics
Mass spectrometry can identify phosphorylation events on recombination factors after checkpoint activation. This reveals signaling networks controlling negative regulation.
Imaging and live-cell analysis
Fluorescence microscopy of tagged proteins (e.g., Pin2/TRF1) can visualize mitotic spindle and recombination foci dynamics. Live-cell imaging quantifies recombination events in real time.
How CRISPR Can Be Used to Study GO:0045950 negative regulation of mitotic recombination
Knockout
CRISPR knockout of negative regulators such as PLK1 or CDK4 can increase mitotic recombination, confirming their inhibitory role. Knockout of Rb1 in breast cancer cells induces synthetic lethality with ATR and PKMYT1 coinhibition, demonstrating the power of KO models in identifying therapeutic targets.
Point Mutation
Point mutations at phosphorylation sites (e.g., Rad54 phospho-dead) can prevent negative regulation and increase recombination. Phospho-mimetic mutations can constitutively suppress recombination.
Knock-in
Knock-in of tagged proteins (e.g., GFP-Pin2/TRF1) allows visualization of mitotic spindle and recombination dynamics. Knock-in of reporter cassettes enables sensitive detection of recombination events.
Overexpression
Overexpression of negative regulators such as DMC1 or Mek1 can attenuate RAD51-mediated recombination. Overexpression models help establish sufficiency of a candidate regulator.
How EDITGENE Supports negative regulation of mitotic recombination Research
Researchers studying negative regulation of mitotic recombination-related genes often need to determine whether a candidate gene is causally involved in suppressing recombination, and which domains or phosphorylation sites mediate this function. EDITGENE provides publication-ready CRISPR cell models and screening services to accelerate this discovery.
Contact EDITGENE today to design your custom CRISPR model for negative regulation of mitotic recombination research.
Frequently Asked Questions About negative regulation of mitotic recombination
What is negative regulation of mitotic recombination (GO:0045950)?
It is any process that inhibits or decreases the rate of DNA recombination during mitosis, as defined by QuickGO.
What genes are involved in negative regulation of mitotic recombination?
Key genes include CDK4, PLK1, Mek1, Rad54, DMC1, Wee1, and Pin2/TRF1, among others.
How does negative regulation of mitotic recombination prevent cancer?
By suppressing loss of heterozygosity and chromosomal rearrangements that can activate oncogenes or lose tumor suppressors.
What is the role of PLK1 in mitotic recombination?
PLK1 regulates the DNA damage response and checkpoint recovery, limiting inappropriate recombination.
How is CDK4 negatively regulated?
Calcineurin, a serine/threonine phosphatase, negatively regulates CDK4, influencing cell-cycle progression and recombination timing.
What is the connection between DMC1 and RAD51?
DMC1 attenuates RAD51-mediated recombination, acting as a negative regulator of recombinase activity.
How do CRISPR knockouts help study negative regulation of mitotic recombination?
Knockout of candidate genes followed by recombination reporter assays can test whether a gene suppresses recombination.
What diseases are linked to defects in negative regulation of mitotic recombination?
Cancer, genome instability syndromes, and loss of heterozygosity disorders.
What model organisms are used to study negative regulation of mitotic recombination?
Saccharomyces cerevisiae, Arabidopsis, and human cell lines are commonly used.
How can EDITGENE help my research on GO:0045950?
EDITGENE provides CRISPR knockout, point-mutation, knock-in, overexpression cell models, library screening, and bioinformatics services.
Conclusion
Negative regulation of mitotic recombination (GO:0045950) is a fundamental biological process that safeguards genome stability by inhibiting inappropriate DNA recombination during mitosis. Its dysregulation is linked to cancer and genome instability, making it a rich area for therapeutic target discovery. CRISPR-based models and screening technologies now enable precise causal interrogation of the genes and mechanisms involved. EDITGENE offers comprehensive services to support these studies from hypothesis to publication.
References
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- 2. Niu H et al.. 2009. Regulation of meiotic recombination via Mek1-mediated Rad54 phosphorylation.. Mol Cell 36(3):393-404 PMID: 19917248
- 3. Chow R et al.. 2007. Mitotic regulation of CDK4 by the serine/threonine phosphatase, calcineurin.. Biochem Biophys Res Commun 363(3):506-12 PMID: 17892862
- 4. Da Ines O et al.. 2022. DMC1 attenuates RAD51-mediated recombination in Arabidopsis.. PLoS Genet 18(8):e1010322 PMID: 36007010
- 5. Li W et al.. 2024. Polo-Like Kinase 1 and DNA Damage Response.. DNA Cell Biol 43(9):430-437 PMID: 38959179
- 6. Coleman TR et al.. 1993. Negative regulation of the wee1 protein kinase by direct action of the nim1/cdr1 mitotic inducer.. Cell 72(6):919-29 PMID: 7681363
- 7. Nakamura M et al.. 2002. Involvement of the telomeric protein Pin2/TRF1 in the regulation of the mitotic spindle.. FEBS Lett 514(2-3):193-8 PMID: 11943150
- 8. Basco RD et al.. 1995. Negative regulation of G1 and G2 by S-phase cyclins of Saccharomyces cerevisiae.. Mol Cell Biol 15(9):5030-42 PMID: 7651421
