GO:0035545 determination of left/right asymmetry in nervous system: Developmental Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0035545 describes the biological process that establishes the nervous system with respect to the left and right body halves.
• Left-right asymmetry in the nervous system is initiated early in development and involves conserved signaling pathways such as Nodal, acting across species from C. elegans to vertebrates.
• Asymmetries are evident in neuronal connectivity, neurotransmitter receptor distribution, and innervation patterns of organs such as the diaphragm and adrenal glands.
• Disruption of left-right asymmetry in the nervous system is associated with neurological and psychiatric conditions, including epilepsy and semantic dementia.
• Key genes orchestrating this process include Nodal, Lefty, Pitx2, and components of the Notch and Wnt pathways, among others.
• Research into GO:0035545 employs CRISPR-based models, imaging, and transcriptomics to dissect the molecular and cellular basis of nervous system asymmetry.
Description
The determination of left/right asymmetry in the nervous system (GO:0035545) is a fundamental developmental process that ensures the nervous system is properly organized along the left-right axis. This asymmetry is critical for correct neural circuit formation and function, influencing behaviors and physiological responses that differ between the two body sides. Understanding this process is essential for researchers studying neurodevelopment, as its disruption can lead to a range of neurological disorders. The process is evolutionarily conserved, with key molecular players identified from invertebrate models such as Caenorhabditis elegans to vertebrates including humans. Studies have revealed that left-right asymmetry in the nervous system involves asymmetric gene expression, neuronal migration, and connectivity, often orchestrated by signaling pathways like Nodal. This article synthesizes current knowledge on GO:0035545, highlighting its definition, mechanisms, associated genes, and research methodologies, to support both basic and translational neuroscience.
determination of left/right asymmetry in nervous system At A Glance
| GO ID | GO:0035545 |
|---|---|
| GO term | determination of left/right asymmetry in nervous system |
| Ontology | biological_process |
| Synonym | none |
| Major function | Establishment of nervous system asymmetry along the left-right axis |
| Related processes | Nodal signaling, neuronal differentiation, axon guidance |
| Key genes | Nodal, Lefty, Pitx2, Notch, Wnt |
| Disease relevance | Neurological disorders, epilepsy, semantic dementia |
What Is GO:0035545?
GO:0035545, determination of left/right asymmetry in nervous system, is defined as the establishment of the nervous system with respect to the left and right halves of the body. This process encompasses the molecular and cellular events that lead to structural and functional differences between the left and right sides of the nervous system, including asymmetric gene expression, neuronal differentiation, and connectivity.
Why Is determination of left/right asymmetry in nervous system Important in Cell Biology?
Understanding GO:0035545 is crucial because left-right asymmetry in the nervous system is a conserved feature that impacts neural circuit function and behavior. Disruptions in this process have been linked to various neurological and psychiatric conditions, making it a target for research into disease mechanisms and potential therapies.
• Elucidates fundamental principles of nervous system development and evolution.
• Provides insights into the molecular basis of asymmetric neural functions, such as lateralized behaviors.
• Links developmental asymmetry to neurological disorders like epilepsy and semantic dementia.
• Informs research on organ innervation asymmetries, including diaphragm and adrenal glands.
• Highlights conserved signaling pathways that can be targeted in regenerative medicine.
• Supports the development of CRISPR-based models to study gene function in asymmetry.
• Aids in understanding how environmental and genetic factors influence brain lateralization.
• Facilitates cross-species comparisons to identify core asymmetry mechanisms.
• Potential implications for understanding neurodevelopmental disorders with asymmetric features.
• Guides experimental design for studying left-right asymmetry in vitro and in vivo.
What Happens During determination of left/right asymmetry in nervous system?
Initiation of Left-Right Asymmetry
In simple terms: The embryo first decides which side will be left and which will be right.
Left-right asymmetry in the nervous system is initiated early in development, often involving the breaking of symmetry by signaling centers such as the node in vertebrates or equivalent structures in invertebrates. In C. elegans, the first signs of asymmetry appear as early as the zygote stage, with asymmetric cell divisions and gene expression patterns. In vertebrates, Nodal signaling plays a central role in establishing left-sided identity, which subsequently influences nervous system development.
Asymmetric Gene Expression and Signaling
In simple terms: Certain genes are turned on only on one side of the embryo, guiding nerve cells to develop differently.
Asymmetric gene expression, particularly of Nodal and its downstream targets such as Pitx2, is a hallmark of left-right asymmetry determination. These genes are expressed on the left side of the embryo and regulate the development of asymmetric neural structures. In C. elegans, asymmetric expression of genes like unc-130 and cog-1 in specific neurons contributes to left-right differences in neuronal identity and connectivity.
Neuronal Differentiation and Migration
In simple terms: Nerve cells are born and move to their correct positions on each side.
Following asymmetric gene expression, neuronal precursors differentiate and migrate to their appropriate locations, forming asymmetric neural circuits. For example, in the developing diaphragm, motor neurons innervate the left and right sides differently, a process dependent on genetic specification. In C. elegans, asymmetric migration of neuroblasts and their progeny leads to left-right differences in neuronal positioning.
Formation of Asymmetric Neural Circuits
In simple terms: The wiring of the nervous system becomes different on the left and right sides.
Asymmetric neural circuits are established through differential axon guidance, synapse formation, and neurotransmitter receptor expression. For instance, dopamine D2 receptor asymmetry in the striatum has been observed, indicating functional lateralization. In the adrenal glands, neural innervation differs between left and right, influencing glucocorticoid production. These asymmetries are critical for proper physiological function and behavior.
Maintenance and Plasticity of Asymmetry
In simple terms: The differences between left and right are kept and can change with experience.
Once established, left-right asymmetry in the nervous system is maintained throughout life, although it can exhibit plasticity in response to environmental factors or injury. For example, glymphatic system dysfunction in temporal lobe epilepsy shows asymmetric patterns, suggesting that asymmetry can be altered in disease states. Similarly, cognitive consequences of asymmetric atrophy in semantic dementia highlight the importance of maintaining proper asymmetry for brain function.
Key Genes Involved in GO:0035545 determination of left/right asymmetry in nervous system
The following genes are key players in the determination of left/right asymmetry in the nervous system, as identified in model organisms and human studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| Nodal | Left-sided signaling molecule that initiates asymmetry | Central to vertebrate left-right axis formation; studied in zebrafish, mouse, and human |
| Lefty | Antagonist of Nodal, restricts its activity to the left side | Regulates the extent of Nodal signaling; important for asymmetric gene expression |
| Pitx2 | Transcription factor downstream of Nodal, expressed on the left side | Controls asymmetric organ development and neural asymmetry |
| Notch | Signaling receptor involved in cell fate decisions | Contributes to asymmetric neuronal differentiation in C. elegans and vertebrates |
| Wnt | Signaling pathway regulating cell polarity and fate | Implicated in left-right asymmetry in various organisms |
| unc-130 | Transcription factor in C. elegans | Regulates asymmetric gene expression in specific neurons |
| cog-1 | Homeodomain protein in C. elegans | Controls left-right asymmetry in gustatory neurons |
| FoxJ1 | Transcription factor regulating cilia formation | Essential for left-right asymmetry in vertebrates by controlling ciliary flow |
| Dnah5 | Axonemal dynein heavy chain | Mutations cause primary ciliary dyskinesia and left-right asymmetry defects |
| Zic2 | Zinc finger transcription factor | Involved in forebrain asymmetry and corpus callosum development |
| Lmo4 | LIM domain transcription factor | Regulates asymmetric development of the nervous system in vertebrates |
| Tbx1 | T-box transcription factor | Associated with asymmetric development of pharyngeal arches and nervous system |
| BMP | Bone morphogenetic protein signaling | Modulates left-right asymmetry in neural tube development |
| FGF | Fibroblast growth factor signaling | Influences asymmetric gene expression in the developing brain |
| Shh | Sonic hedgehog signaling | Regulates left-right asymmetry in the nervous system and other organs |
| Hox | Homeobox transcription factors | Contribute to regionalization and asymmetry in the nervous system |
| Dopamine receptor D2 | Neurotransmitter receptor | Shows left-right asymmetry in the striatum, affecting motor and cognitive functions |
| Glucocorticoid receptor | Nuclear receptor | Mediates asymmetric glucocorticoid production in adrenal glands |
How Is determination of left/right asymmetry in nervous system Regulated?
The determination of left/right asymmetry in the nervous system is regulated by a complex interplay of signaling pathways, including Nodal, Notch, Wnt, and BMP, which are themselves subject to feedback and crosstalk. In C. elegans, asymmetric gene expression is controlled by a network of transcription factors and microRNAs that ensure robust left-right differences. In vertebrates, the Nodal-Lefty-Pitx2 pathway is a central regulatory module, with Lefty acting as a feedback inhibitor of Nodal. Additionally, ciliary motility and fluid flow at the embryonic node are critical for initiating asymmetric signals. Environmental factors and epigenetic modifications may also influence the stability of asymmetry.
determination of left/right asymmetry in nervous system and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Nodal | Left-right asymmetry defects, congenital heart disease | Knockout mouse, zebrafish |
| Pitx2 | Axenfeld-Rieger syndrome, asymmetric organ defects | Conditional knockout mouse |
| Dnah5 | Primary ciliary dyskinesia with situs inversus | Point mutation mouse model |
| Zic2 | Holoprosencephaly, brain asymmetry disorders | Knockout mouse |
| Dopamine receptor D2 | Asymmetric motor dysfunction in Parkinson's disease | Overexpression rat model |
Neurological Disorders with Asymmetric Features
Disruptions in left-right asymmetry of the nervous system have been associated with various neurological disorders. For instance, temporal lobe epilepsy patients exhibit asymmetric glymphatic system dysfunction, which may contribute to seizure lateralization. Similarly, semantic dementia is characterized by asymmetric brain atrophy, leading to cognitive deficits that differ based on the side of atrophy. These findings suggest that proper left-right asymmetry is crucial for normal brain function, and its perturbation can manifest as disease.
Developmental and Psychiatric Implications
Alterations in left-right asymmetry during development have been linked to psychiatric conditions such as schizophrenia and autism, although the exact mechanisms remain under investigation. The Nodal signaling pathway, critical for asymmetry, has been implicated in mood disorders and has been studied for its role in brain lateralization. Understanding these connections may provide insights into the developmental origins of psychiatric diseases.
Organ Innervation Asymmetries and Disease
Asymmetric innervation of organs, such as the diaphragm and adrenal glands, can have physiological consequences. For example, asymmetric motor innervation of the diaphragm muscles is genetically specified, and its disruption may lead to respiratory defects. In adrenal glands, left-right differences in neural innervation affect glucocorticoid production, which can influence stress responses and metabolic diseases. These examples highlight the broader impact of nervous system asymmetry on organ function and disease.
From determination of left/right asymmetry in nervous system-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of Nodal in nervous system asymmetry? | Knockout mouse or zebrafish |
| How does a specific point mutation in Pitx2 affect neural development? | Point mutation knock-in mouse |
| Can overexpression of Lefty rescue asymmetry defects? | Overexpression transgenic zebrafish |
| Where is Pitx2 expressed during development? | Tagged knock-in reporter mouse |
| What are the downstream targets of Nodal in the nervous system? | RNA-seq after Nodal knockout |
| How does asymmetric innervation of the diaphragm develop? | Conditional knockout of motor neuron genes in mouse |
How to Study the determination of left/right asymmetry in nervous system Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout | Gene function loss | Study essentiality of asymmetry genes |
| CRISPR knock-in | Tagged protein expression | Visualize asymmetric protein localization |
| RNA-seq | Transcriptome-wide gene expression | Identify asymmetric gene expression |
| Proteomics | Protein abundance and modifications | Discover asymmetric protein distribution |
| Two-photon imaging | Neural activity and structure | Observe asymmetric circuits in vivo |
| DTI-ALPS | Glymphatic function asymmetry | Assess asymmetry in epilepsy patients |
| Behavioral assays | Lateralized behavior | Link asymmetry to function |
Genetic Knockout and Knock-in Models
CRISPR-Cas9 technology enables the generation of knockout and knock-in models to study gene function in left-right asymmetry. For example, knockout of Nodal or Pitx2 in mice or zebrafish can reveal their essential roles in nervous system asymmetry. Knock-in of fluorescent tags allows visualization of asymmetric gene expression patterns in vivo.
Transcriptomic and Proteomic Profiling
RNA sequencing (RNA-seq) and proteomics can identify asymmetric gene expression and protein distribution in the nervous system. Comparing left and right sides of the brain or specific nuclei can uncover novel asymmetry genes. Single-cell RNA-seq further resolves cell-type-specific asymmetries.
Imaging and Connectomics
Advanced imaging techniques, such as two-photon microscopy and diffusion tensor imaging (DTI), allow visualization of asymmetric neural circuits and connectivity. In model organisms, fluorescent reporters and calcium imaging can track neuronal activity asymmetries.
Behavioral Assays for Lateralization
Behavioral tests in model organisms can assess functional consequences of nervous system asymmetry. For instance, lateralized behaviors in C. elegans or mice can be linked to specific asymmetric neurons. Such assays complement molecular and anatomical studies.
How CRISPR Can Be Used to Study GO:0035545 determination of left/right asymmetry in nervous system
Knockout
CRISPR knockout of genes such as Nodal, Pitx2, or Dnah5 in model organisms can abolish left-right asymmetry in the nervous system, revealing their essential roles. For example, Nodal knockout in zebrafish results in randomized organ laterality and neural asymmetry defects.
Point Mutation
Introducing specific point mutations via CRISPR can model human disease variants. For instance, a point mutation in Dnah5 associated with primary ciliary dyskinesia can be knocked into mice to study its impact on nervous system asymmetry.
Knock-in
Knock-in of reporter genes, such as GFP, into endogenous loci allows real-time visualization of asymmetric gene expression. This approach has been used to track Pitx2 expression in the developing brain.
Overexpression
CRISPR activation (CRISPRa) or transgenic overexpression can elevate gene expression to study gain-of-function effects. Overexpressing Lefty on the right side can disrupt asymmetry, demonstrating its role as a Nodal antagonist.
How EDITGENE Supports determination of left/right asymmetry in nervous system Research
Researchers studying determination of left/right asymmetry in nervous system-related genes often need to determine whether a candidate gene is causally involved in the process or merely correlated with asymmetric phenotypes. EDITGENE provides comprehensive CRISPR-based services to enable such functional studies with precision and efficiency.
Contact EDITGENE today to design your custom CRISPR model for determination of left/right asymmetry in nervous system research.
Frequently Asked Questions About determination of left/right asymmetry in nervous system
What is GO:0035545?
GO:0035545 is the Gene Ontology term for the biological process of determining left/right asymmetry in the nervous system, which establishes nervous system structures with respect to the left and right body halves.
What genes are involved in determination of left/right asymmetry in nervous system?
Key genes include Nodal, Lefty, Pitx2, Notch, Wnt, and Dnah5, among others, which regulate asymmetric gene expression and neural development.
Why is left/right asymmetry in the nervous system important?
It is crucial for proper neural circuit formation and function, and its disruption is linked to neurological disorders such as epilepsy and semantic dementia.
How is left/right asymmetry established in the nervous system?
It is initiated by asymmetric signaling, often involving Nodal, leading to differential gene expression, neuronal differentiation, and circuit formation on the left and right sides.
What diseases are associated with defects in nervous system asymmetry?
Conditions such as temporal lobe epilepsy, semantic dementia, and certain psychiatric disorders have been associated with altered left-right asymmetry.
Can CRISPR be used to study left/right asymmetry in the nervous system?
Yes, CRISPR knockout, knock-in, and overexpression models in various organisms allow functional dissection of genes involved in asymmetry.
What model organisms are used to study GO:0035545?
Common models include C. elegans, zebrafish, and mice, which offer genetic tractability and conserved asymmetry mechanisms.
What are the molecular mechanisms of left/right asymmetry in the nervous system?
Mechanisms involve Nodal signaling, asymmetric transcription factor activity (e.g., Pitx2), and differential axon guidance and synapse formation.
How does left/right asymmetry affect behavior?
Asymmetry can lead to lateralized behaviors, such as handedness in humans or specific turning behaviors in invertebrates, reflecting underlying neural circuit differences.
What research methods are used to study nervous system asymmetry?
Methods include CRISPR gene editing, RNA-seq, proteomics, advanced imaging (e.g., two-photon, DTI), and behavioral assays.
Conclusion
The determination of left/right asymmetry in the nervous system (GO:0035545) is a fundamental developmental process with far-reaching implications for neural function and disease. Research across model organisms has elucidated conserved molecular pathways, particularly Nodal signaling, that orchestrate asymmetric gene expression and circuit formation. Disruptions in this process are associated with neurological and psychiatric conditions, underscoring its clinical relevance. Continued investigation using CRISPR-based models and advanced omics technologies will further unravel the complexities of nervous system asymmetry and may inform therapeutic strategies.
References
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- 3. Signore IA et al.. 2016. Nodal signalling and asymmetry of the nervous system.. Philos Trans R Soc Lond B Biol Sci 371(1710) PMID: 27821531
- 4. Larisch R et al.. 1998. Left-right asymmetry of striatal dopamine D2 receptors.. Nucl Med Commun 19(8):781-7 PMID: 9751933
- 5. Saxu R et al.. 2023. Asymmetries of Left and Right Adrenal Glands in Neural Innervation and Glucocorticoids Production.. Int J Mol Sci 24(24) PMID: 38139285
- 6. Charoy C et al.. 2017. Genetic specification of left-right asymmetry in the diaphragm muscles and their motor innervation.. Elife 6 PMID: 28639940
- 7. Zhao X et al.. 2023. The asymmetry of glymphatic system dysfunction in patients with temporal lobe epilepsy: A DTI-ALPS study.. J Neuroradiol 50(6):562-567 PMID: 37301366
- 8. Woollams AM et al.. 2018. Cognitive consequences of the left-right asymmetry of atrophy in semantic dementia.. Cortex 107:64-77 PMID: 29289335
