SYCE1 is one of the proteins required for the early assembly of the central element. SYCE1 ensures that the exchange between chromosomes occurs at the correct position for pairing, which helps to form genetic diversity. The complete structure of the synaptonemal complex is one of the signals for the continuation of meiosis, and the loss of SYCE1 will lead to meiotic arrest. Synaptonemal Complex Central Element Protein 1 (SYCE1) is a key meiosis-related gene, mainly expressed in germ cells. SYCE1 mutations can be caused by the following reasons:
- Hereditary mutations: Familial mutations, which are recessive.
- DNA damage induced by environmental factors: Such as radiation, chemicals or viral infections may damage the SYCE1 gene region.
- Chromosome structural abnormalities: Such as microdeletions or translocations may affect the expression or structural integrity of the SYCE1 gene region.
Related Products
Structure and Function of SYCE1 Protein
- Lateral Elements: formed along each homologous chromosome.
- Central Element: connects two lateral elements to ensure chromosome pairing.
- Transverse Filaments: connects lateral elements to central elements.
SYCE1 Expression Location and Time
- Tissue-specific expression: SYCE1 is mainly expressed in the testis and ovary, especially in the early stages of meiosis in spermatogonia and oocytes.
- Time-specific expression: Its expression peak occurs in prophase I of meiosis, especially in the coupling and synapsis stages.
Physiological Activity of SYCE1 Gene
SYCE1 is a highly conserved gene that encodes a protein that is crucial in the process of meiosis and is mainly involved in the formation and function of the synaptonemal complex (SC). SYCE1 plays a vital role in the early stage of meiosis, especially in the formation of the synaptonemal complex (SC):
- Synaptonemal complex assembly: SYCE1 is an important component of the central element, maintaining the pairing and stable connection of homologous chromosomes.
- Initiation of homologous recombination: It is a key step in meiosis by stabilizing chromosome pairing and promoting the occurrence of genetic recombination.
- Prerequisite for chromosome separation: Without the normal function of SYCE1, chromosomes cannot complete accurate separation, resulting in meiotic failure.
Functional Stages of SYCE1 in Meiosis
| Stages |
Function of SYCE1 |
| Prophase I - coupling phase |
Participates in the initial formation of the synaptonemal complex and promotes homologous chromosomes to find a "mate" |
| Prophase I - synapomorphy |
Synaptonemal complex is stably formed, and chromosomes are stably bound to each other through SYCE1 |
| Prophase I - diplotene and beyond |
Synaptonemal complex disintegrates, and SYCE1 function gradually terminates |
Pathologies Caused by SYCE1 Gene Mutation
After the SYCE1 gene mutates, its functional loss or abnormality will directly affect the meiotic process, and then cause the following lesions:
Defective Synaptonemal Complex
The mutated SYCE1 protein cannot form or cannot stably participate in the complex structure.
Meiotic Arrest
Homologous chromosomes cannot pair correctly, resulting in meiosis being interrupted in the early stage.
Spermatogenesis Disorder
Spermatogonia cannot differentiate into mature sperm, resulting in spermatogenesis disorder.
Testicular Tissue Structure Changes
There are no mature sperm in the seminiferous tubules, and "Sertoli cell only syndrome" is common.
SYCE1 Gene Mutation Causes Non-obstructive Azoospermia
Non-obstructive azoospermia (NOA) is a state of azoospermia caused by impaired sperm production in the testicle itself. In patients with SYCE1 mutations, NOA has the following characteristics:
- Recessive inheritance pattern: Testicular volume is usually normal or slightly small, but testicular puncture shows azoospermia.
- Hormone levels may be elevated: FSH (follicle-stimulating hormone) is elevated, indicating impaired testicular function.
- Testicular biopsy results: show spermatogonial arrest or severe defects in sperm production.
- High risk of assisted reproduction failure: due to the absence of functional sperm, the success rate of sperm retrieval is extremely low.
Abnormal Expression of SYCE1 Gene Causes Non-obstructive Azoospermia
The expression and function of SYCE1 gene are essential for the normal progress of meiosis. It ensures the correct pairing, recombination and separation of homologous chromosomes by participating in the core structure of the synaptonemal complex, and is an important guarantee for maintaining the genetic stability of germ cells. SYCE1 gene plays a key role in the human male reproductive system. Its mutation can seriously interfere with meiosis and is one of the important genetic factors leading to non-obstructive azoospermia. In-depth research on SYCE1 mutation will help:
- Assist in the diagnosis of the genetic cause of NOA
- Guide individualized treatment and fertility planning
- Develop cutting-edge treatment strategies such as gene editing.
References
- Maor-Sagie, E., et al. Deleterious mutation in SYCE1 is associated with non-obstructive azoospermia. Journal of assisted reproduction and genetics. 2015, 32: 887-891.
- Bolcun-Filas, E., et al. Mutation of the mouse Syce1 gene disrupts synapsis and suggests a link between synaptonemal complex structural components and DNA repair. PLoS genetics. 2009, 5(2): e1000393.
.
