SORBS2 transcription is activated by telomere position effect–over long distance upon telomere shortening in muscle cells from patients with facioscapulohumeral dystrophy

SORBS2 gene expression in skeletal muscle biopsies. Immunohistochemistry (IHC) staining of transversal biopsies of cardiac (A) and skeletal (B) muscle for the detection of SORBS2 (Epitomics, RB19714). (C) RT-PCR of a SORBS2 transcript variant (Exon 17–42) in skeletal muscle biopsies from biceps (bic) and deltoid (del) isolated from FSHD patients (FSHD A, B) and their unaffected siblings (control) for a total of 12 cohorts. For each sample, three PCRs were performed using 35, 40, or 45 amplification cycles. In these RT-PCR assays, all transcript variants that include exons 17 and 42 (23 variants, including eight protein-coding forms) are amplified.