GC-1 spg cells are most similar to Leydig cells, a testis somatic cell-type, and not germ cells

GC-1 spg is an immortalized cell line derived from an adult mouse testis and reported to be most similar to spermatocytes, a male germ cell-type. However, immunofluorescence indicates that GC-1 spg cells express WT1, a marker of testis somatic cells, and do not express markers of germ cells. Transcriptomic profiling indicate GC-1 cells are most similar to Leydig cells. Therefore, we conclude that GC-1 spg cells are most similar to testis somatic cells.