Hnrnpu, also known as scaffold attachment factor A (SAF-A), is a nuclear protein involved in diverse biological functions. It plays crucial roles in RNA splicing, chromatin organization, and regulating gene expression, DNA replication, genome integrity, and mitotic fidelity. These functions are vital for developmental processes, especially in the formation of the human brain [3,4].

In mouse models, conditional loss of hnRNPU in prospermatogonia arrests spermatogenesis and leads to sterility, highlighting its essential role in establishing the spermatogonial stem cell pool [2]. In Sertoli cells, conditional knockout of hnRNPU causes severe testicular atrophy and male sterility, as it is required for neonatal Sertoli cell and pre-pubertal testicular development [5]. In bladder cancer cell lines, knockout of Hnrnpu in high-expressing cells inhibits cell proliferation, invasion, and migration, promotes apoptosis and S-phase arrest when treated with cisplatin, suggesting its association with cisplatin resistance [1].

In summary, Hnrnpu is essential for multiple biological processes such as spermatogenesis, testicular development, and has implications in cancer drug resistance. Studies using gene knockout and conditional knockout mouse models have significantly enhanced our understanding of Hnrnpu's role in these processes and disease conditions, providing potential therapeutic targets for male infertility and cisplatin-resistant bladder cancer.