Zfp42, also known as Rex1 (reduced expression gene 1), is a zinc-finger protein that has been associated with pluripotency/multipotency in embryonic stem cells. It is involved in various biological processes such as early embryogenesis, spermatogenesis, and may play a role in epigenetic regulation, including genomic imprinting [3].

In gene-knockout mouse models, Rex1(-/-) male mice show an age-associated decrease in sperm counts, abnormal sperm morphology, and mild testicular atrophy, indicating its importance in testicular function [4]. In embryonic stem cell differentiation, disruption of the Rex1 gene enhanced the expression of ectoderm, mesoderm, and endoderm markers, suggesting it acts to reduce retinoic-acid-induced differentiation [5]. In the context of glaucoma, in vitro experiments showed that Zfp42 reduces the damage of retinal ganglion cells by up-regulating the expression of MARK2 [1]. In colorectal cancer, CPNE7 interacts with NONO to initiate Zfp42 transcription, promoting tumorigenesis, and Zfp42 knockdown inhibits tumor cell proliferation and migration while promoting apoptosis [2].

In summary, Zfp42 is involved in multiple biological processes including stem cell-related functions, testicular development, and disease-related processes such as glaucoma and colorectal cancer. The use of gene-knockout mouse models has been crucial in revealing its role in these areas, helping to understand the underlying mechanisms and potentially providing new therapeutic targets for related diseases.