VCX3A, a member of the VCX/VCY gene family, is predominantly expressed in the spermatogonia of the male testis, and emerging evidence has linked mutations or duplication of the gene to nonobstructive azoospermia. Although VCX3A had previously been characterized as a nuclear RNA-binding protein, its actual functional role inside spermatogonial cells remained poorly defined. A new study published in Cell & Bioscience now reports that VCX3A acts as a splicing regulator that enhances the proliferation and migration of spermatogonia-derived cells, providing what the authors describe as direct mechanistic evidence linking the protein to the post-transcriptional control of spermatogonial cell behavior.
The research team began by surveying the VCX gene cluster and found that among its members, VCX3A showed the highest expression in human testicular tissue. Functional experiments then revealed a consistent pattern across two cell models. When VCX3A was added exogenously to GC-1 cells, a mouse spermatogonial cell line, the cells proliferated and migrated more vigorously. Conversely, when endogenous VCX3A was knocked down in NCCIT cells, a human embryonal carcinoma line used as an additional model, both behaviors were suppressed. These gain- and loss-of-function results point to VCX3A as a positive regulator of the proliferative and motile capacity of these cells.
To understand how the protein works at the molecular level, the researchers turned to biophysical analyses. These showed that VCX3A is an intrinsically disordered protein, meaning it lacks a fixed three-dimensional structure, and that it undergoes liquid–liquid phase separation both in vitro and within the nuclei of GC-1 and NCCIT cells.
The study then mapped what VCX3A binds to. irCLIP-seq profiling demonstrated that the protein binds preferentially to the intronic regions of protein-coding genes, with a marked enrichment of an RRDGG motif among its binding sites. Complementary proteomic work using immunoprecipitation followed by mass spectrometry, together with co-immunoprecipitation assays, confirmed that VCX3A interacts with KHDRBS1, a known splicing regulator, and associates with the pre-mRNAs transcribed from genes governing cell motility and proliferation, including Lpp and Frmd5.
The functional consequence of these interactions was a change in how the affected genes are processed. VCX3A modulated the alternative splicing of the Lpp and Frmd5 pre-mRNAs, thereby increasing the abundance of specific transcript isoforms.
Two final experiments tied the mechanism together. Deleting the RGG-like domain of VCX3A disrupted its splicing-regulatory activity, and knocking down Khdrbs1, the gene encoding its interaction partner, produced the same disruption. In both cases, the stimulatory effects of VCX3A on GC-1 cell proliferation and migration were abolished. This indicates that both the RGG-like domain and cooperation with KHDRBS1 are required for VCX3A to influence cell behavior through pre-mRNA splicing.
The authors conclude that VCX3A is an RNA-binding protein that cooperates with KHDRBS1 in GC-1 cells to coordinately regulate the alternative splicing of pre-mRNAs derived from motility- and proliferation-related genes such as Lpp and Frmd5, thereby enhancing the proliferative and migratory capacity of these cells. Because the work was carried out in cell lines, including a mouse spermatogonial line and a human embryonal carcinoma line rather than primary human spermatogonia, the findings will need to be tested in more physiological settings before their implications for male fertility can be fully assessed. The study was published as open access research on 12 October 2026, and the released version is an early, citable accepted manuscript that remains subject to further edits before the final Version of Record appears.
Subject of Research: The role of the RNA-binding protein VCX3A in regulating alternative splicing, proliferation and motility of spermatogonial cells
Article Title: The VCX/VCY gene family member VCX3A encodes an RNA-binding protein that modulates the proliferation and motility of spermatogonia GC-1 cells via pre-mRNA splicing
Article References: Wang, W., Gao, F., Dong, X., Tian, S., Xiong, C., Wang, Y., Fu, Y., Jiao, H., Li, X., Wei, F., Xu, Y., & Shi, W. (2026). The VCX/VCY gene family member VCX3A encodes an RNA-binding protein that modulates the proliferation and motility of spermatogonia GC-1 cells via pre-mRNA splicing. Cell & Bioscience. https://doi.org/10.1186/s13578-026-01667-z
Image Credits: AI Generated
DOI: 10.1186/s13578-026-01667-z
Keywords: VCX3A, VCX/VCY gene family, RNA-binding protein, alternative splicing, spermatogonia, GC-1 cells, KHDRBS1, liquid-liquid phase separation, nonobstructive azoospermia, Lpp, Frmd5, pre-mRNA splicing
News Source: Drew Townsend. (October 29, 2026). RNA-Binding Protein VCX3A Drives Spermatogonial Cell Proliferation and Motility Through Splicing Control. Scienmag.
