Fig. 2

NMDAR subunit expression profile of chondrifying chicken micromass cultures during the entire culturing period (days 0–6). a. Protein expression profiles of GluN1, GluN2A, GluN2B, GluN3A and GluN3B subunits in total cell lysates (n = 3 for each culturing day). b. Protein expression profiles of GluN1, GluN2B, GluN3A and GluN3B subunits in the membrane fraction (n = 3 for each culturing day). Immunoblotting for GluN2A in the membrane fraction has also been performed but no bands at the expected size were detected (see Additional file 1: Fig. S2 in the Online Resource). Optical densities of bands from 3 parallel experiments were pooled and presented as bar graphs ± SEM, along with representative membrane images from a single experiment. The representative membrane images are out of 3 independent experiments, each showing a similar expression profile. For the total lysates, data normalization was performed by normalizing each data to the optical density values of the loading control (GAPDH) on the same day, and then to the day 0 cultures. For the membrane fraction, optical density values were normalized to the day 0 cultures. Significant (*P < 0.05) changes in protein levels of the mean optical densities of each day from 3 experiments relative to the previous day (mean) are marked