Figure 4
![Figure 4](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fscrt7/MediaObjects/13287_2009_Article_7_Fig4_HTML.jpg)
Relative mRNA abundance of COL1A1 and DBI nonnormalized and normalized with three or five internal control genes. Pattern of COL1A1 and DBI expression before and after normalization by using a NF calculated with three or five most-stable internal control genes from geNorm analysis (see Figure 3). * P < 0.05 for Tissue × Day interaction; #P < 0.05 for Differentiation × Day interaction at each time point. See Table S3 for overall statistical results.