GO:0090220 chromosome localization to nuclear envelope involved in homologous chromosome segregation: Meiotic Chromosome Dynamics, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0090220 describes the directed movement of chromosomes to the nuclear envelope that precedes synapsis and contributes to homologous chromosome segregation.
• This process is a prerequisite for faithful homologous recombination and proper chromosome segregation during meiosis.
• Key proteins include meiosis-specific telomere-associated proteins such as TERB1 (CCDC79) and nuclear envelope components like MAN1 and emerin.
• Disruption of this process leads to defective synapsis, chromosome mis-segregation, and meiotic arrest, which can cause infertility and aneuploidy.
• Model organisms including mouse, maize, and C. elegans have been instrumental in defining the genetic requirements for chromosome localization to the nuclear envelope.
• CRISPR-based knockout, knock-in, and live imaging approaches enable precise functional dissection of this conserved meiotic pathway.
Description
GO:0090220, chromosome localization to nuclear envelope involved in homologous chromosome segregation, is a biological process that describes the directed movement of chromosomes to the nuclear envelope, a step that precedes synapsis and is required for homologous chromosome segregation during meiosis. This process is essential for the proper spatial organization of chromosomes, allowing homologous chromosomes to find each other and form crossovers, which are critical for genetic diversity and accurate chromosome segregation. In many organisms, telomeres attach to the nuclear envelope and move to facilitate homologous pairing, a phenomenon known as the telomere-led bouquet formation. The nuclear envelope thus serves as a platform for chromosome dynamics, and its components, such as MAN1 and emerin, are directly involved in chromosome segregation and cell division. Research into GO:0090220 has revealed that meiosis-specific proteins, such as mouse CCDC79 (TERB1), are essential for tethering telomeres to the nuclear envelope and for the progression of meiosis. In maize, the desynaptic (dy) mutation disrupts the link between nuclear morphology, telomere distribution, and synapsis, leading to meiotic chromosome mis-segregation. These findings underscore the importance of chromosome localization to the nuclear envelope for fertility and genome stability. Understanding GO:0090220 is therefore critical for researchers studying meiosis, infertility, and aneuploidy. This article synthesizes the current knowledge on the molecular players, regulatory mechanisms, and experimental models used to investigate this process, providing a resource for both basic and translational research.
chromosome localization to nuclear envelope involved in homologous chromosome segregation At A Glance
| GO ID | GO:0090220 |
|---|---|
| GO term | chromosome localization to nuclear envelope involved in homologous chromosome segregation |
| Ontology | biological_process |
| Synonym | chromosome localisation to nuclear envelope involved in homologous chromosome segregation |
| Definition | The directed movement of a chromosome to the nuclear envelope that contributes to homologous chromosome segregation and precedes synapsis. |
| Major function | Facilitates homologous chromosome pairing and segregation during meiosis by positioning chromosomes at the nuclear envelope. |
| Related processes | Homologous chromosome segregation, synapsis, telomere tethering, meiotic recombination. |
| Key cellular structures | Nuclear envelope, telomeres, synaptonemal complex. |
| Organisms studied | Mus musculus, Zea mays, Caenorhabditis elegans. |
What Is GO:0090220?
GO:0090220 is defined as the directed movement of a chromosome to the nuclear envelope that contributes to homologous chromosome segregation and precedes synapsis. In simpler terms, it is the process by which chromosomes, often via their telomeres, attach to and move along the nuclear envelope to facilitate the pairing of homologous chromosomes before they synapse. This step is a prerequisite for the formation of the synaptonemal complex and for the proper segregation of homologous chromosomes during the first meiotic division.
Why Is chromosome localization to nuclear envelope involved in homologous chromosome segregation Important in Cell Biology?
Chromosome localization to the nuclear envelope is a fundamental step in meiosis that ensures homologous chromosomes are correctly positioned for pairing, synapsis, and recombination. Defects in this process lead to meiotic arrest, chromosome mis-segregation, and aneuploidy, which are associated with infertility and developmental disorders. Moreover, nuclear envelope proteins such as MAN1 and emerin have been linked to chromosome segregation and cell division, highlighting the broader relevance of this process to genome stability. Understanding GO:0090220 therefore has implications for reproductive biology, cancer, and rare genetic diseases.
• Ensures faithful homologous chromosome segregation during meiosis I.
• Prevents aneuploidy and meiotic arrest, which can cause infertility.
• Facilitates the telomere-led bouquet formation required for homologous pairing.
• Involves nuclear envelope proteins like MAN1 and emerin that are linked to cell division and chromosome segregation.
• Disruption of this process is associated with defective synapsis and recombination.
• Provides a model for studying nuclear envelope-chromosome interactions.
• Relevant to understanding the etiology of some cases of male and female infertility.
• Potential target for contraceptives and fertility treatments.
• Contributes to genome stability and prevents chromosomal abnormalities.
• Conserved across eukaryotes, enabling comparative studies.
What Happens During chromosome localization to nuclear envelope involved in homologous chromosome segregation?
Telomere Attachment to the Nuclear Envelope
In simple terms: Telomeres, the ends of chromosomes, attach to the inner nuclear membrane.
The first step in chromosome localization to the nuclear envelope is the attachment of telomeres to the nuclear envelope. In mouse meiosis, the meiosis-specific protein CCDC79 (TERB1) is essential for this tethering, as it localizes to telomeres and is required for their attachment to the nuclear envelope. This attachment is mediated by interactions with nuclear envelope proteins and is a prerequisite for subsequent chromosome movements.
Chromosome Movement and Bouquet Formation
In simple terms: Chromosomes move along the nuclear envelope to cluster their telomeres, forming a bouquet-like structure.
After attachment, chromosomes undergo directed movement along the nuclear envelope, leading to the clustering of telomeres at one pole of the nucleus, a configuration known as the bouquet. In maize, the desynaptic (dy) mutation disrupts this process, resulting in abnormal nuclear morphology and telomere distribution, which impairs synapsis. This movement is thought to facilitate the search for homologous partners and to promote recombination.
Homologous Pairing and Synapsis
In simple terms: Homologous chromosomes find each other and pair along their lengths, forming the synaptonemal complex.
The movement of chromosomes to the nuclear envelope brings homologous chromosomes into close proximity, enabling them to pair and synapse. Synapsis involves the formation of the synaptonemal complex, a proteinaceous structure that holds homologs together and facilitates crossing over. Defects in chromosome localization to the nuclear envelope, as seen in the maize dy mutant, lead to defective synapsis and subsequent chromosome mis-segregation.
Nuclear Envelope Remodeling and Chromosome Segregation
In simple terms: The nuclear envelope changes to allow chromosomes to separate properly.
Following synapsis and recombination, the nuclear envelope undergoes remodeling to permit chromosome segregation. Nuclear envelope proteins such as MAN1 and emerin have overlapping functions essential for chromosome segregation and cell division in C. elegans. Their depletion leads to defects in chromosome segregation, highlighting the role of the nuclear envelope in this process.
Key Genes Involved in GO:0090220 chromosome localization to nuclear envelope involved in homologous chromosome segregation
The following genes and proteins have been experimentally implicated in chromosome localization to the nuclear envelope involved in homologous chromosome segregation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TERB1 (CCDC79) | Meiosis-specific telomere-associated protein; required for telomere attachment to nuclear envelope | Mouse knockout leads to meiotic arrest and defective chromosome localization |
| MAN1 | Nuclear envelope protein; involved in chromosome segregation and cell division | C. elegans studies show overlapping function with emerin in chromosome segregation |
| Emerin | Nuclear envelope protein; involved in chromosome segregation and cell division | C. elegans studies show overlapping function with MAN1 |
| Desynaptic (dy) | Maize gene; defines a pathway linking nuclear morphology, telomere distribution, and synapsis | Maize dy mutation causes defective synapsis and chromosome mis-segregation |
| SUN1 | Nuclear envelope protein; links telomeres to cytoskeleton | Inferred from general meiosis studies; not directly cited in provided references |
| SUN2 | Nuclear envelope protein; links telomeres to cytoskeleton | Inferred from general meiosis studies; not directly cited in provided references |
| KASH5 | Outer nuclear membrane protein; connects telomeres to cytoskeleton | Inferred from general meiosis studies; not directly cited in provided references |
| LINC complex | Linker of nucleoskeleton and cytoskeleton; mediates chromosome movement | Inferred from general meiosis studies; not directly cited in provided references |
| Cohesin | Holds sister chromatids together; involved in chromosome segregation | Inferred from general meiosis studies; not directly cited in provided references |
| SYCP1 | Synaptonemal complex protein; required for synapsis | Inferred from general meiosis studies; not directly cited in provided references |
| SYCP3 | Synaptonemal complex protein; required for synapsis | Inferred from general meiosis studies; not directly cited in provided references |
| DMC1 | Meiosis-specific recombinase; involved in homologous recombination | Inferred from general meiosis studies; not directly cited in provided references |
| RAD51 | Recombinase; involved in homologous recombination | Inferred from general meiosis studies; not directly cited in provided references |
| H2AX | Histone variant; marks DNA double-strand breaks | Inferred from general meiosis studies; not directly cited in provided references |
| ATM | Kinase; regulates DNA damage response and meiosis | Inferred from general meiosis studies; not directly cited in provided references |
| SPO11 | Topoisomerase-like protein; initiates meiotic recombination | Inferred from general meiosis studies; not directly cited in provided references |
How Is chromosome localization to nuclear envelope involved in homologous chromosome segregation Regulated?
The regulation of chromosome localization to the nuclear envelope is not fully understood, but it is likely controlled by cell cycle kinases and nuclear envelope remodeling factors. In mouse, TERB1 is a meiosis-specific protein whose expression is tightly regulated during meiotic prophase. The maize desynaptic (dy) mutation suggests that this process is genetically regulated and linked to nuclear morphology. However, specific regulatory pathways such as mTOR or ISR have not been directly implicated in the provided references.
chromosome localization to nuclear envelope involved in homologous chromosome segregation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TERB1 (CCDC79) | Meiotic arrest, infertility | Mouse knockout |
| MAN1 | Chromosome segregation defects, cell division abnormalities | C. elegans knockout |
| Emerin | Emery-Dreifuss muscular dystrophy, chromosome segregation defects | C. elegans knockout |
| Desynaptic (dy) | Male sterility, defective synapsis | Maize mutant |
Meiotic Defects and Infertility
Disruption of chromosome localization to the nuclear envelope leads to meiotic arrest and defective synapsis, which are common causes of infertility in humans. Mouse models lacking TERB1 exhibit meiotic arrest, highlighting the importance of this process for gamete production. Similarly, the maize dy mutation causes male sterility due to defective chromosome segregation.
Aneuploidy and Developmental Disorders
Failure of homologous chromosome segregation can result in aneuploidy, a condition associated with developmental disorders such as Down syndrome and miscarriage. Nuclear envelope proteins like MAN1 and emerin are essential for chromosome segregation, and their dysfunction may contribute to aneuploidy.
Nuclear Envelopathies
Mutations in nuclear envelope proteins, such as emerin, cause Emery-Dreifuss muscular dystrophy and other nuclear envelopathies. While the link to chromosome localization is not fully established, the role of emerin in chromosome segregation suggests that defects in this process may contribute to disease pathology.
From chromosome localization to nuclear envelope involved in homologous chromosome segregation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate chromosome localization to the nuclear envelope? | Knockout mouse or C. elegans |
| What is the role of a specific point mutation in TERB1? | Point-mutation knock-in mouse |
| How does a disease-associated variant affect nuclear envelope tethering? | Knock-in of human variant in mouse |
| Where does protein X localize during meiosis? | Tagged knock-in (e.g., GFP) in mouse |
| Can overexpression of gene X rescue meiotic defects? | Overexpression transgenic mouse |
| What are the downstream targets of gene X? | CRISPR library screening in cell culture |
How to Study the chromosome localization to nuclear envelope involved in homologous chromosome segregation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live imaging | Chromosome movement and telomere dynamics | Visualizing bouquet formation in meiosis |
| Immunofluorescence | Protein localization and synapsis | Assessing synaptonemal complex formation |
| Electron microscopy | Ultrastructure of nuclear envelope and chromosomes | Detailing attachment sites |
| Knockout models | Gene function in vivo | Testing requirement for TERB1 in mice |
| Mutant analysis | Phenotypic consequences of mutations | Characterizing maize dy mutant |
| Proteomics | Protein interactions and complexes | Identifying novel nuclear envelope proteins |
| CRISPR screening | Genome-wide identification of regulators | Discovering new genes in cell culture |
Live Imaging of Chromosome Dynamics
Live imaging using fluorescently tagged telomere proteins (e.g., GFP-TERB1) allows real-time visualization of chromosome movement to the nuclear envelope in meiotic cells. This method can reveal defects in bouquet formation and synapsis in mutant models.
Immunofluorescence and Electron Microscopy
Immunofluorescence against synaptonemal complex proteins (e.g., SYCP1, SYCP3) and telomere markers can assess synapsis and chromosome localization. Electron microscopy provides ultrastructural details of the nuclear envelope and chromosome attachments.
Genetic Knockout and Mutant Analysis
Knockout mice or mutant organisms (e.g., maize dy) are used to determine the requirement for specific genes in chromosome localization. Phenotypic analysis includes meiotic staging, chromosome spreads, and fertility tests.
Proteomics and Interaction Studies
Proteomic approaches such as immunoprecipitation coupled with mass spectrometry can identify novel components of the chromosome localization machinery. Yeast two-hybrid and co-immunoprecipitation can validate interactions between telomere proteins and nuclear envelope components.
How CRISPR Can Be Used to Study GO:0090220 chromosome localization to nuclear envelope involved in homologous chromosome segregation
Knockout
CRISPR knockout of candidate genes such as TERB1 in mouse models has demonstrated its essential role in telomere attachment and chromosome localization to the nuclear envelope. Knockout studies in C. elegans have revealed overlapping functions of MAN1 and emerin in chromosome segregation.
Point Mutation
Point mutations can be introduced to dissect specific domains of proteins involved in chromosome localization. For example, mutating the telomere-binding domain of TERB1 could reveal its importance for nuclear envelope tethering.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) allows live imaging of proteins like TERB1 during meiosis. Knock-in of human disease variants into mouse models can test their impact on chromosome localization.
Overexpression
Overexpression of nuclear envelope proteins or telomere-associated proteins can test sufficiency for chromosome localization or rescue of mutant phenotypes. However, careful controls are needed to avoid artifacts.
How EDITGENE Supports chromosome localization to nuclear envelope involved in homologous chromosome segregation Research
Researchers studying chromosome localization to nuclear envelope involved in homologous chromosome segregation-related genes often need to determine whether a candidate gene is causally involved in this process or is merely a bystander. EDITGENE provides a comprehensive suite of CRISPR-based services to enable precise functional interrogation of these genes in relevant cell models and organisms.
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Frequently Asked Questions About chromosome localization to nuclear envelope involved in homologous chromosome segregation
What is GO:0090220?
GO:0090220 is a Gene Ontology biological process term that describes the directed movement of a chromosome to the nuclear envelope that contributes to homologous chromosome segregation and precedes synapsis.
What genes are involved in chromosome localization to the nuclear envelope?
Key genes include TERB1 (CCDC79) in mouse, MAN1 and emerin in C. elegans, and the desynaptic (dy) gene in maize.
Why is chromosome localization to the nuclear envelope important?
It ensures homologous chromosomes are correctly positioned for pairing, synapsis, and recombination, which are essential for faithful chromosome segregation and fertility.
What happens if chromosome localization to the nuclear envelope fails?
Failure leads to defective synapsis, meiotic arrest, chromosome mis-segregation, and aneuploidy, which can cause infertility and developmental disorders.
How is chromosome localization to the nuclear envelope studied?
It is studied using live imaging, immunofluorescence, electron microscopy, genetic knockouts, and proteomics in model organisms like mouse, maize, and C. elegans.
What is the role of TERB1 in this process?
TERB1 is a meiosis-specific telomere-associated protein required for telomere attachment to the nuclear envelope in mouse meiosis.
How do MAN1 and emerin function in chromosome segregation?
MAN1 and emerin have overlapping functions essential for chromosome segregation and cell division in C. elegans.
What is the maize desynaptic (dy) mutation?
The dy mutation defines a pathway linking nuclear morphology, telomere distribution, and synapsis, and causes defective meiotic chromosome segregation.
Can CRISPR be used to study this process?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable precise functional dissection of genes involved in chromosome localization.
What diseases are associated with defects in this process?
Defects are associated with infertility, aneuploidy, and potentially nuclear envelopathies such as Emery-Dreifuss muscular dystrophy.
Conclusion
GO:0090220, chromosome localization to nuclear envelope involved in homologous chromosome segregation, is a critical meiotic process that ensures proper chromosome pairing and segregation. Research in model organisms has identified key proteins such as TERB1, MAN1, and emerin, and has linked defects in this process to infertility and aneuploidy. Continued investigation using advanced CRISPR and imaging technologies will further elucidate the molecular mechanisms and regulatory networks governing this process, with potential implications for reproductive medicine and cancer biology.
References
- 1. Daniel K et al.. 2014. Mouse CCDC79 (TERB1) is a meiosis-specific telomere associated protein.. BMC Cell Biol 15:17 PMID: 24885367
- 2. Liu J et al.. 2003. MAN1 and emerin have overlapping function(s) essential for chromosome segregation and cell division in Caenorhabditis elegans.. Proc Natl Acad Sci U S A 100(8):4598-603 PMID: 12684533
- 3. Murphy SP et al.. 2012. The maize (Zea mays) desynaptic (dy) mutation defines a pathway for meiotic chromosome segregation, linking nuclear morphology, telomere distribution and synapsis.. J Cell Sci 125(Pt 15):3681-90 PMID: 22553213
