Nup210l, encoding a testis-specific nucleoporin, is likely involved in nuclear trafficking. It may play a crucial role in regulating the process of spermiogenesis, potentially by controlling the entry of histone variants/transition proteins/protamines into the nucleus and the replacement of core histones [2].

In a study on an infertile man with uncondensed sperm heads and histone retention, a homozygous loss-of-function variant in NUP210L was identified [2]. Mouse models also provided insights. Mice with a homozygous transgene intronic insertion in Nup210l were infertile, and spermatozoa had mild anomalies in head morphology and decreased motility, though nuclear compaction and histone removal seemed unaffected [1]. Re-analyzing the patient's exome data, a rare, potentially pathogenic, heterozygous variant in nucleoporin gene NUP153 was found, and NUP210L and NUP153 were shown to colocalize at the caudal nuclear pole in elongating spermatids and spermatozoa in mouse and human [1].

In conclusion, Nup210l is essential for male fertility, as demonstrated by gene-knockout mouse models and human genetic studies. Its absence leads to sperm defects, highlighting its significance in spermatogenesis. Understanding Nup210l's function could potentially improve the genetic diagnosis of male infertility [1,2].