Normalisation of desmin mRNA expression to various combinations of the geometric average of three genes. Data shown are all calculated relative to day 2, so that day 2 values are equal to 1 arbitrary unit (A.U.). Four normalisation factors were derived by calculating the geometric averages of the following gene combinations: A: EF1α, RNApolII, Hprt1 (closed circle); B: EF1α, Ppia, Hprt1 (open circle); C: EF1α, RNApolII, Ppia (closed triangle); D: Ppia, Hprt1, RNApolII (open triangle). Values shown are the mean normalised value ± S.E. (n = 6).