Fig. 4. The regulation of EIIIA and 4 integrin expression. (A,B) EIIIA expression in dermal fibroblasts cultured in hanging drops for 24, 48 or 72 hours. RT-PCR for Actin, total Fibronectin and the EIIIA exon were performed. Fibronectin expression was normalized to Actin expression. There was a small decrease in Fibronectin expression between t₀ (100%) and t₄₈ (92.8%), and, a noticeable decrease at t₇₂ (64.1%; A). EIIIA expression was normalized to Fibronectin expression. During the same time-lapse, the portion of Fibronectin-expressing cells containing the EIIIA exon decreased from 59.4% to 24.3% (B). (C,D) Cells were placed in adherent culture with or without BMP2 and BMP7 (0.5 µg/ml) for 20 hours. Then RT-PCR to detect EIIIA and integrin 4 expression was performed. The portion of Fibronectin-expressing cells containing the EIIIA exon decreased with BMP2 treatment, from 61.1% to 34.4%, whereas BMP7 treatment led to a slight decrease, 53.1% (C). BMP2 treatment led to an increase of 4 integrin expression, from 100% to 125.29%, whereas BMP7 induced only a non-significant increase (105.5%; D).