Figure 1

Myogenic cells from different individuals have consistently different and stable frequencies of DUX4-FL expression. (A) Myogenic cells from different individuals have different extents of DUX4-FL expression. DUX4-FL expression frequency (number of DUX4-FL-positive nuclei per 10,000 nuclei in myosin-positive cells) was measured in multiple independent cultures of differentiated myogenic cells from three FSHD patients (07Abic, 09Abic, and 17Abic; red) and their unaffected (control) family members (07Ubic, 09Ubic, 17Ubic, and 17Vbic, respectively; green). Within each family, FSHD cells had a significantly higher frequency of DUX4-FL expression than control cells (P < 0.01; t-tests; n = 12 to 14). DUX4-FL expression frequencies of cells from each FSHD patient also differed significantly from each other, with 17Abic > 09Abic > 07Abic (P < 0.01; t-tests; n = 12 to 14). Red open diamonds = FSHD; green open diamonds = unaffected control; horizontal bar = average; average ± SE and ‘n’ are shown below each culture name. (B) DUX4-FL expression frequency does not show a clear change upon serial subculture. Cultures of cells from the same FSHD and controls as in (A) were serially subcultured through 6-7 passages, and DUX4-FL expression frequency was measured at each passage in differentiated cultures as described in the ‘Methods.’ Each point (closed red squares for FSHD, closed green circles for controls) shows results for a single passage, with the passage number increasing from left to right in sequence. The beginning and ending number of total population doublings (PD) for each cell strain is shown below the name (e.g., for 07Abic, the cells were first examined at PD = 28 and these reached PD = 47 at the final passage examined).