At p4, all five cell lines exhibited enhanced expression of nine genes (ZFP42, TDGF1, SFRP2, PODXL, NR6A1, CD9, DNMT3B, IFITM1, and LIN28), which are all related to stemness, and reduced expression of four genes (TAT, PAX4, IAPP, and DDX4), which are related to differentiation (Figure 1(c)).
GATA6, AFP, and DDX4 were used as endodermal, KDR and ACTC1 as mesodermal, NEUROD1 and PAX6 as ectodermal markers, and KRT7 as a trophoblast marker (Supplementary Figure 3).
DDX4 and StAR showed no variation in their expression, while KIT, CYP11, SF1, and SOX9 showed less variation at p9.
The antibodies used in this study were anti-TDRD12 (1:200), Lectin-peanut agglutinin (PNA) (1:2,000, Molecular Probes, Eugene, OR, USA), TDRD1 (1:200, R&D systems, Minneapolis, MN, USA), and DEAD-box helicase 4 (DDX4) (1:500, Abcam, Cambridge, UK) antibodies.
DDX4 was detected in the cytoplasm of spermatocyte and chromatoid body of round spermatid (Figure 2A).
All primers/probes (DDX4, STELLA, Oct4, SCP3 and 18S rRNA as internal control) and also master mix were from Applied Biosystems (Applied Biosystems, Foster City, CA, USA).
The cells were incubated in 3% [H.sub.2][O.sub.2] in PBS for 15 mins to block endogenous peroxidase and then incubated with anti Oct4, Nanog, SSEA4, DDX4 and C-kit antibody overnight at 4 [degrees]C.
The academics, led by Dr Jonathan Tilly of Massachusetts General Hospital, managed to identify and extract human stem cells that can go on to become immature eggs, because all carry a unique protein called DDX4
To characterize the concentration, integrity, and stability of cfsRNA, we selected the transcripts of 2 genes: ACTB (actin, beta)  and DDX4 [DEAD (AspGlu-Ala-Asp) box polypeptide 4], a germ cell-specific gene.
We used full-length PCR amplicons of human ACTB and DDX4 transcripts as calibrators to quantify their different regions.
Early in human development, Smith explains, cells that eventually become part of the male or female reproductive system express two proteins, DDX4