Mthfd2 expression level in ribozyme clones and in FRDA patient's fibroblasts. (A) Quantitative-RT-PCR analyses were performed on three different cellular RNA extracts of R2m and R2C1 clones, comparing the expression of murine Mthfd2 transcript to the reference Hprt transcript. The R2C1 cells used for these experiments present the "adjusted" frataxin residual level of 29 ± 7%. (B). Quantitative-RT-PCR analyses were performed on two different cellular RNA extracts of FRDA (n = 3) and control (n = 5) fibroblasts, comparing expression of the human MTHFD2 transcript to 18S ribosome transcript. ***p ≤ 0.005.