Isolation, Characterization, and In Vitro Culturing of Spermatogonial Stem Cells in Japanese Quail (Coturnix japonica).

We reported previously testis-mediated germline chimera production and characterization of germline stem cell-like cells from chicken testes. The present study aimed to establish an in vitro system for culture of quail spermatogonial stem cells (SSCs) for practical applications in germline preservation and transgenesis. Testicular cells (TCs) from juvenile (4 weeks old) or adult (8 weeks old) quail testis were isolated using sequential enzymatic digestion. The percentages of viability of isolated TCs were 91.00% ± 2.12% and 88.00% ± 1.87% in juvenile and adult testes, respectively, and immunohistochemical evaluation indicated the expression of integrin alpha-6 (ITGA6), GDNF family receptor alpha-1 (GFRA1), and Deleted in azoospermia-like (DAZL) in specific TCs. SSCs were purified by differential plating of TCs and then subjected to quantitative reverse transcription-polymerase chain reaction, which showed differential expression of SSC-specific, and germness and stemness-related genes. Coculture of quail SSCs with mouse embryonic fibroblasts and Sertoli cells as a feeder layer resulted in the generation of stable SSC colonies and short-term cultivation, and the expression of SSC and germ cell markers was maintained during several passages of culture. Collectively, these results demonstrate the efficient isolation and characterization of quail SSCs and the suitability of Sertoli cells as a feeder layer for in vitro culture of quail SSCs. Quail SSCs will facilitate the production of germline chimeras and transgenesis.