FMRP control of isoform switching regulates nucleus/cytoplasmic distribution of MBNL1.

(A) Schematic illustration of Mbnl1 isoforms (modified from Tabaglio and colleagues [35]). Exons 5 and 7 are the most frequently alternatively spliced exons. Created with Biorender.com. (B) RT-PCR of Mbnl1 isoforms from control and Fmr1-depleted cell. At right is quantification of band intensities of exons 5 and 7 and mean ± SD is shown (Student’s t test, **p Mbnl1 RNA expression between the genotypes. (C) MBNL1 isoforms in the cytoplasm and nucleus in control and Fmr1 knockdown cells. Lamin B1 and GAPDH served as makers for the nuclear and cytoplasmic fractions, respectively. Quantification of the upper and lower MBNL1 bands relative to Lamin B1 or GAPDH is indicated. Mean ± SD is shown (Student’s t test, *p Fmr1 depletion. Quantification of the nucleus/cytoplasmic ratio of MBNL1 fluorescence intensity is at right. Mean ± SD is shown (Student’s t test, **p S3 Data.