Figure 1.
A) Schematic representation of primary Nodal signaling events. B) Microarray results (NimbleGen HG18 chip) of mRNA from human embryonic stem cells (hESC-H9), melanoma (C8161) and breast cancer (MDA-MB-231) cell lines showing wide variability in detection levels between 16 different probes all designated as recognizing Nodal. C) Results from PCR experiments show that primers corresponding to the Affymetrix U133B chip 237896_AT microarray probe produce a single PCR product that corresponds to the Nodal gene, while sequencing of the two PCR products recognized by the 230916_AT probe do not correspond to the Nodal gene. D) Semi-quantitative PCR analyses in human embryonic stem cells (H9), and human embryonic kidneys cells (HEK293T), poorly aggressive (c81-61), and highly aggressive (C8161) human melanoma cells with primers spanning the exon 2/exon 3 boundary identifies two bands which may indicate splice variants of Nodal (RT cntrl = no reverse transcriptase present).