Ccdc188, also known as coiled-coil domain containing 188, is a gene with testis-enriched expression. It is crucial for male fertility and is likely involved in pathways related to spermatozoa development [1]. The study of its function has been facilitated by genetic models, especially knockout mouse models.

Using the CRISPR/Cas9 system to generate a Ccdc188 knockout mouse line, it was found that Ccdc188 knockout male mice were sterile. Most of the Ccdc188-null spermatozoa were acephalic. Transmission electron microscopy showed that although the sperm head-to-tail coupling apparatus could assemble without CCDC188, it failed to attach to the nucleus during spermiogenesis, leading to sperm head and neck separation. Also, almost all spermatozoa in the cauda epididymis lacked a mitochondrial sheath [1].

In conclusion, CCDC188 plays a vital role in forming a tight sperm head-neck junction, which is essential for male fertility. The Ccdc188 knockout mouse model has significantly contributed to understanding the molecular mechanism underlying male infertility caused by acephalic spermatozoa syndrome [1].