RETRACTED: Bone morphogenetic protein 4 (BMP4) induces buffalo (Bubalus bubalis) embryonic stem cell differentiation into germ cells (Retracted Article)

The aim of the present study was to investigate the effect of Bone morphogenetic protein 4 (BMP4) stimulation on differentiation of buffalo embryonic stem (ES) cells into germ lineage cells. ES cells were subjected to in vitro differentiation in floating and adherent cultures, under different BMP4 concentrations (20, 50 and 100 ngml(-1)) for different culture intervals (4, 8 and 14 days). qPCR analysis revealed that BMP4 at a concentration of 50-100 ngml(-1) for a culture period of 14 days led to maximum induction of germ lineage genes like DAZL, VASA, PLZF (PGC-specific); SYCP3, MLH1, TNP1/2 and PRM2 (Meiotic genes); BOULE and TERT1 (Spermatocyte markers); GDF9, ZP2 and 3 (Oocyte markers). The expression levels of all the genes were significantly higher under BMP4 differentiation as compared to BMP4 + NOGGIN and spontaneously differentiated cultures. Immunocytochemical analysis of embryoid bodies (EBs) and monolayer adherent cultures revealed expression of PGC- (c-KIT, DAZL and VASA); Meiotic- (SYCP3, MLH1 and PROTAMINE1); Spermatocyte- (ACROSIN and HAPRIN); and Oocyte- markers (GDF9 and ZP4). Western blotting was positive for VASA, GDF9 and ZP4. Oocyte-like structures (OLS) obtained in monolayer differentiated cultures harbored a big nucleus and a ZP4 coat. They showed embryonic development and progressed through 2-cell, 4-cell, 8-cell and blastocyst-like structures. Global DNA methylation analysis showed significantly (p < 0.05) decreased levels of 5-methyl-2-deoxycytidine in EBs obtained in optimum differentiation medium. The expression of meiotic markers coupled with expression of spermatocyte and oocyte markers is an indication of post-meiotic progression into spermatogenesis and oogenesis, respectively. (C) 2015 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.