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.

Nuclear reprogramming in cell–free extracts

Methods for directly turning a somatic cell type into another type (a process referred to as transdifferentiation) would be beneficial for producing replacement cells for therapeutic applications. Adult stem cells have been shown to display a broader differentiation potential than anticipated and may contribute to tissues other than those in which they reside. In addition, novel transdifferentiation strategies are being developed. I report recent results on the functional reprogramming of a somatic cell using a nuclear and cytoplasmic extract derived from another somatic cell type. The reprogramming of 293T fibroblasts in an extract from T cells is evidenced by nuclear uptake and the assembly of transcription factors, induction of activity of a chromatin remodelling complex, changes in chromatin composition and activation of lymphoid cell–specific genes. The reprogrammed cells express T–cell–specific surface molecules and a complex regulatory function. Reprogramming cells in cell–free extracts may create possibilities for producing replacement cells for therapeutic applications. The system may also constitute a powerful tool to examine the mechanisms of nuclear reprogramming, at least as they occur in vitro .