GO:0001675 acrosome assembly: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0001675 acrosome assembly is the biological process in which the acrosome is formed from the Golgi apparatus of the spermatid.
• Acrosome assembly depends on microtubule organization and the manchette, a transient microtubular structure that helps shape the sperm head.
• Multiple genes, including CFAP65, CFAP300, MYCBPAP, CCDC38, and Calicin, are required for normal acrosome biogenesis in mice and humans.
• Defects in acrosome assembly cause male infertility, often presenting as asthenoteratozoospermia or primary ciliary dyskinesia with abnormal sperm morphology.
• The process is experimentally tractable using knockout, point-mutation, knock-in, and overexpression models in mice and cell lines.
• Studying acrosome assembly informs reproductive biology, fertilization, and the diagnosis of human male infertility.
Description
Acrosome assembly (GO:0001675) is the biological process by which the acrosome, a specialized secretory vesicle at the anterior pole of the sperm head, is formed from the Golgi apparatus of the spermatid. This process is essential for fertilization because the acrosome contains hydrolytic enzymes that enable the sperm to penetrate the zona pellucida of the egg. In mammals, acrosome assembly occurs during spermiogenesis and is tightly coupled to the reorganization of the spermatid cytoskeleton, particularly the microtubular manchette. Disruption of acrosome assembly leads to malformed sperm heads and male infertility in both mice and humans. Consequently, researchers studying reproductive biology, fertilization, and andrology need reliable models to dissect the genetic and cellular control of this process.
acrosome assembly At A Glance
| GO ID | GO:0001675 |
|---|---|
| GO term | acrosome assembly |
| Ontology | biological_process |
| Synonym | acrosome formation |
| Major function | Formation of the acrosome from the spermatid Golgi |
| Cellular context | Spermatid (male germ cell) during spermiogenesis |
| Key structures | Golgi apparatus, acrosomic vesicle, manchette microtubules |
| Related processes | Spermiogenesis, fertilization, sperm head shaping |
What Is GO:0001675?
According to the Gene Ontology, acrosome assembly (GO:0001675) is defined as the formation of the acrosome from the spermatid Golgi. It is a biological process that encompasses the vesicular trafficking, membrane remodeling, and cytoskeletal interactions required to build the acrosomal cap. The synonym acrosome formation is often used interchangeably in the literature.
Why Is acrosome assembly Important in Cell Biology?
Acrosome assembly is critical for male fertility because the acrosome is indispensable for sperm-egg interaction and penetration of the zona pellucida. Defects in this process result in abnormal sperm morphology (teratozoospermia) and reduced motility (asthenozoospermia), leading to male infertility. Understanding acrosome assembly also illuminates fundamental mechanisms of vesicle trafficking, cytoskeletal organization, and organelle biogenesis during spermatogenesis.
• Acrosome assembly is required for the formation of a functional acrosome, which is essential for fertilization.
• Disruption of acrosome assembly causes teratozoospermia and male infertility in humans and mice.
• The process is linked to primary ciliary dyskinesia when ciliary genes such as CFAP300 are mutated.
• Acrosome assembly depends on the manchette, a microtubular structure that also shapes the sperm head.
• Genes such as CFAP65, CCDC38, and MYCBPAP are directly implicated in acrosome biogenesis.
• Studying acrosome assembly provides insights into Golgi-derived vesicle trafficking and cytoskeletal dynamics.
• Acrosome assembly is a target for reproductive toxicology and male contraceptive research.
• Animal models of acrosome assembly defects help diagnose and classify human male infertility.
• The process is conserved in mammals, making bovine and murine models informative.
• Research on acrosome assembly contributes to assisted reproductive technologies and fertility preservation.
What Happens During acrosome assembly?
Golgi-derived vesicle formation
In simple terms: The acrosome starts as small vesicles that bud off from the Golgi apparatus in the spermatid.
During early spermiogenesis, the Golgi apparatus produces proacrosomic vesicles that contain acrosomal enzymes and membrane proteins. These vesicles are transported along microtubules toward the nuclear surface, where they coalesce to form a single acrosomic granule. Proper Golgi function and vesicle trafficking are prerequisites for acrosome assembly.
Acrosomic granule and cap formation
In simple terms: The vesicles fuse into a granule that spreads over the nucleus to form the acrosomal cap.
The acrosomic granule attaches to the nuclear envelope and flattens to form the acrosomal cap, which covers the anterior portion of the sperm head. This step requires interactions between the acrosomal membrane and the underlying nuclear envelope, and it is influenced by perinuclear theca proteins such as Calicin. Calicin helps shape the sperm head and maintain nuclear structure, and its loss leads to abnormal acrosome formation.
Manchette microtubule organization
In simple terms: A transient skirt of microtubules, called the manchette, helps position the acrosome and elongate the sperm head.
The manchette is a microtubular structure that surrounds the spermatid nucleus during elongation. It is required for the transport of vesicles and proteins to the developing acrosome, and disruption of microtubule organization impairs acrosome assembly. Proteins such as CFAP65 and CCDC38 are associated with the manchette and are necessary for normal acrosome biogenesis.
Nuclear shaping and acrosome anchoring
In simple terms: The nucleus condenses and changes shape, and the acrosome stays attached to the front of the sperm head.
As the spermatid nucleus condenses, the acrosome remains anchored to the nuclear envelope via specialized structures including the perinuclear theca. Calicin is a perinuclear theca protein that helps maintain nuclear structure and sperm head shape; its deficiency results in abnormal acrosome morphology. This anchoring is essential for the acrosome to function during fertilization.
Final maturation and spermiation
In simple terms: The acrosome matures, and the sperm is released from the testis.
After the acrosomal cap is fully formed, the spermatid undergoes further maturation, including mitochondrial sheath assembly and tail formation. Defects in acrosome assembly often coincide with abnormalities in the mitochondrial sheath and flagellum, as seen in CFAP65 and CFAP300 mutants. The mature sperm is then released during spermiation, ready for transport through the male reproductive tract.
Key Genes Involved in GO:0001675 acrosome assembly
The following genes have been experimentally linked to acrosome assembly or acrosome biogenesis in mice and humans.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CFAP65 | Acrosome biogenesis and mitochondrial sheath assembly | Knockout causes abnormal acrosome and mitochondrial sheath defects |
| CFAP300 | Sperm flagellar assembly and acrosome formation | Loss-of-function variant causes primary ciliary dyskinesia and male infertility |
| MYCBPAP | Acrosome biogenesis, manchette structure, sperm tail assembly | Homozygous deleterious variants cause asthenoteratozoospermia |
| CCDC38 | Acrosome biogenesis and fibrous sheath assembly | Knockout leads to acrosome and fibrous sheath defects in mice |
| Calicin (CLGN) | Perinuclear theca protein, sperm head shaping, nuclear structure | Deficiency causes abnormal sperm head and acrosome morphology |
| Golgi apparatus proteins | Vesicle formation for acrosome assembly | General role in proacrosomic vesicle budding |
| Microtubule subunits | Manchette formation and vesicle transport | Required for acrosome assembly and sperm head elongation |
| Zona pellucida proteins | Sperm-egg interaction after acrosome reaction | Relevant to fertilization studies |
| Bovine spermatogenesis genes | Comparative models of acrosome assembly | Bovine models inform mammalian reproduction |
| Other manchette proteins | Cytoskeletal support for acrosome assembly | Candidate genes for male infertility |
| Mitochondrial sheath proteins | Energy for sperm motility | Often co-affected with acrosome defects |
| Fibrous sheath proteins | Structural support of flagellum | Co-affected in CCDC38 mutants |
| Primary ciliary dyskinesia genes | Cilia and flagella function | Link acrosome assembly to ciliary disorders |
| Perinuclear theca proteins | Nuclear shaping and acrosome anchoring | Calicin is a key example |
| Golgi trafficking regulators | Vesicle transport to acrosome | Potential targets for functional studies |
| Spermatid-specific transcription factors | Regulation of acrosome genes | Emerging area in spermatogenesis research |
How Is acrosome assembly Regulated?
Acrosome assembly is regulated by the coordinated expression of genes involved in Golgi function, vesicle trafficking, and microtubule organization. The manchette, a microtubular structure, is dynamically regulated during spermiogenesis and is essential for proper acrosome positioning. Proteins such as CFAP65 and CCDC38 are required for normal acrosome biogenesis, and their loss disrupts the process. Additionally, perinuclear theca proteins like Calicin contribute to nuclear shaping and acrosome anchoring, indicating that structural regulation is critical. Hormonal and paracrine factors that control spermatogenesis also indirectly influence acrosome assembly, as reviewed in bovine models.
acrosome assembly and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MYCBPAP | Asthenoteratozoospermia with abnormal acrosome biogenesis | Knockout mouse, patient-derived cells |
| CFAP300 | Primary ciliary dyskinesia and male infertility | Knockout mouse, human cell lines |
| CFAP65 | Acrosome biogenesis and mitochondrial sheath defects | Knockout mouse |
| CCDC38 | Acrosome biogenesis and fibrous sheath defects | Knockout mouse |
| Calicin (CLGN) | Abnormal sperm head shape and nuclear structure | Knockout mouse |
Male infertility and asthenoteratozoospermia
Defects in acrosome assembly are a major cause of male infertility, often presenting as asthenoteratozoospermia characterized by abnormal sperm morphology and reduced motility. Homozygous deleterious variants in MYCBPAP cause abnormal acrosome biogenesis, manchette structure, and sperm tail assembly in humans and mice. Similarly, loss of CFAP65 leads to acrosome biogenesis defects and mitochondrial sheath abnormalities.
Primary ciliary dyskinesia
Mutations in ciliary genes such as CFAP300 can cause primary ciliary dyskinesia, which is associated with male infertility due to disrupted sperm flagellar assembly and acrosome formation. This highlights a shared molecular basis between ciliary function and acrosome assembly.
Teratozoospermia and sperm head abnormalities
Disruption of perinuclear theca proteins such as Calicin results in abnormal sperm head shape and nuclear structure, which are linked to acrosome malformation. CCDC38 deficiency in mice also causes acrosome biogenesis defects and fibrous sheath abnormalities, contributing to teratozoospermia.
From acrosome assembly-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate acrosome assembly? | Knockout mouse or CRISPR KO cell line |
| Does a patient variant impair acrosome formation? | Point-mutation knock-in mouse or cell line |
| Can wild-type gene rescue the phenotype? | Knock-in or overexpression rescue model |
| Where does the protein localize during acrosome assembly? | Tagged knock-in (e.g., GFP) mouse or cell line |
| Does overexpression of gene X alter acrosome assembly? | Overexpression cell model or transgenic mouse |
| What pathways interact with gene X? | CRISPR library screening and bioinformatics |
How to Study the acrosome assembly Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Transmission electron microscopy (TEM) | Acrosome ultrastructure and manchette organization | Assessing acrosome assembly defects |
| Immunofluorescence | Protein localization in spermatids | Validating acrosome and manchette markers |
| RNA-seq | Transcriptional changes in mutant testes | Identifying pathways affected by gene loss |
| Proteomics | Protein expression and interactions | Discovering acrosome assembly complexes |
| CRISPR knockout | Gene function loss | Testing causality of candidate genes |
| Point-mutation knock-in | Effect of patient variants | Modeling human infertility mutations |
| In vitro fertilization | Sperm-egg interaction and penetration | Functional fertility assessment |
| Bioinformatics analysis | Gene ontology and pathway enrichment | Interpreting omics data in acrosome assembly |
Genetic knockout and knock-in models
CRISPR/Cas9-mediated knockout mice and cell lines are widely used to study acrosome assembly genes such as CFAP65, CCDC38, and MYCBPAP. Point-mutation knock-in models can replicate patient variants to assess pathogenicity. These models allow researchers to observe acrosome morphology, sperm head shape, and fertility outcomes.
Imaging and histology
Transmission electron microscopy (TEM) and immunofluorescence are standard for visualizing acrosome structure and manchette organization during spermiogenesis. These methods reveal defects in acrosomal cap formation, nuclear shaping, and microtubule organization.
Proteomics and transcriptomics
RNA-seq and proteomics can identify dysregulated genes and proteins in knockout models, providing insights into the molecular pathways affected by loss of acrosome assembly genes. Such analyses help link candidate genes to specific stages of acrosome assembly.
Fertilization assays
In vitro fertilization (IVF) assays using sperm from mutant models can assess the functional consequence of acrosome assembly defects on sperm-egg binding and penetration. These assays are critical for translating morphological findings into fertility outcomes.
How CRISPR Can Be Used to Study GO:0001675 acrosome assembly
Knockout
CRISPR knockout of genes such as CFAP65, CCDC38, and MYCBPAP in mice or cell lines recapitulates acrosome assembly defects and provides direct evidence of gene function. These models are essential for understanding the genetic basis of male infertility.
Point Mutation
Point-mutation knock-in models introduce specific patient variants (e.g., in CFAP300 or MYCBPAP) to assess their impact on acrosome assembly and sperm function. Such models help distinguish pathogenic variants from benign polymorphisms.
Knock-in
Knock-in of tagged versions of acrosome proteins (e.g., GFP-Calicin) allows real-time visualization of protein localization during acrosome assembly. Rescue experiments with wild-type knock-in can confirm that a gene is necessary and sufficient for normal acrosome formation.
Overexpression
Overexpression of candidate genes in spermatid cell lines or transgenic mice can test whether excess protein disrupts acrosome assembly. This approach is useful for studying dominant-negative effects or gain-of-function mutations.
How EDITGENE Supports acrosome assembly Research
Researchers studying acrosome assembly-related genes often need to determine whether a candidate gene is causally involved in the process or merely correlated with it. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell and animal models, enabling functional validation of genes implicated in acrosome assembly and male infertility.
Contact EDITGENE today to design your custom CRISPR model for acrosome assembly research.
Frequently Asked Questions About acrosome assembly
What is acrosome assembly?
Acrosome assembly (GO:0001675) is the biological process in which the acrosome is formed from the Golgi apparatus of the spermatid.
What genes are involved in acrosome assembly?
Genes such as CFAP65, CFAP300, MYCBPAP, CCDC38, and Calicin have been experimentally linked to acrosome assembly.
What is the GO ID for acrosome assembly?
The Gene Ontology ID for acrosome assembly is GO:0001675.
Why is acrosome assembly important for fertility?
The acrosome is required for sperm to penetrate the egg's zona pellucida, so defects in its assembly cause male infertility.
What diseases are associated with defective acrosome assembly?
Defects are associated with asthenoteratozoospermia, primary ciliary dyskinesia, and teratozoospermia.
How can I study acrosome assembly in the lab?
Common methods include CRISPR knockout, point-mutation knock-in, TEM, immunofluorescence, and IVF assays.
What is the role of the manchette in acrosome assembly?
The manchette is a microtubular structure that helps transport vesicles and shape the sperm head during acrosome assembly.
Which model organisms are used to study acrosome assembly?
Mice are the most common model, but bovine models also provide insights into mammalian spermatogenesis.
Can CRISPR be used to study acrosome assembly?
Yes, CRISPR knockout and knock-in models are widely used to test gene function in acrosome assembly.
What happens if acrosome assembly fails?
Failure results in malformed sperm heads, abnormal acrosomes, and reduced fertility or infertility.
Conclusion
Acrosome assembly (GO:0001675) is a specialized biological process essential for male fertility, involving Golgi-derived vesicle trafficking, manchette microtubule organization, and nuclear shaping. Mutations in genes such as CFAP65, CFAP300, MYCBPAP, CCDC38, and Calicin disrupt this process and cause male infertility in humans and mice. Continued research using CRISPR models and advanced imaging will further elucidate the molecular mechanisms and identify therapeutic targets for reproductive disorders.
References
- 1. Litscher ES et al.. 2025. The mammalian egg's zona pellucida, fertilization, and fertility.. Curr Top Dev Biol 162:207-258 PMID: 40180510
- 2. Barth A et al.. 2025. Bovine Spermatogenesis.. Adv Anat Embryol Cell Biol 240:65-136 PMID: 40272587
- 3. Zhang XZ et al.. 2022. The perinuclear theca protein Calicin helps shape the sperm head and maintain the nuclear structure in mice.. Cell Rep 40(1):111049 PMID: 35793634
- 4. Zhou Y et al.. 2025. Homozygous deleterious variants in MYCBPAP induce asthenoteratozoospermia involving abnormal acrosome biogenesis, manchette structure and sperm tail assembly in humans and mice.. Sci China Life Sci 68(3):777-792 PMID: 39704931
- 5. Yin HY et al.. 2025. CFAP300 loss-of-function variant causes primary ciliary dyskinesia and male infertility via disrupting sperm flagellar assembly and acrosome formation.. Asian J Androl 27(6):743-750 PMID: 40898687
- 6. Wang W et al.. 2021. CFAP65 is required in the acrosome biogenesis and mitochondrial sheath assembly during spermiogenesis.. Hum Mol Genet 30(23):2240-2254 PMID: 34231842
- 7. Moreno RD et al.. 2006. Assembly of spermatid acrosome depends on microtubule organization during mammalian spermiogenesis.. Dev Biol 293(1):218-27 PMID: 16540102
- 8. Wang Y et al.. 2024. Coiled-coil domain-containing 38 is required for acrosome biogenesis and fibrous sheath assembly in mice.. J Genet Genomics 51(4):407-418 PMID: 37709195
