Altered Focal Adhesion in Pitx2 Mutant Myogenic Cells.
Muscle progenitor cells were isolated from E12.5 forelimb tissue of Pitx2LacZ/+ (A, C, E) and Pitx2LacZ/LacZ (B, D, F) mice. Cells were stained with alexa 488 phalloidin, (F-actin), talin (focal adhesions) and beta-Gal(Pitx2) (A–F). (G) Myogenic cells had a mean ± standard error of the mean (SEM) of 26±4 (total = 475) for HET and 18±1 (total = 330) for MUT of focal adhesions per cell (n = 18). This difference in mean focal adhesion number was determined statistically significant using a two-tailed unpaired t-test (p = 0.0464). The distribution of the number focal adhesions between the leading and trailing edges of the muscle progenitor cells was not affected; the leading edges had an mean ± SEM of 14±2 (total = 255) for HET and 9±1 (total = 170) for MUT cells, while at the trailing edges had means ± SEM of 12±2 (total = 220) for HET and 9±1 (total = 160) for MUT cells. Neither of the differences of focal adhesion number at leading or trailing edges between HET and MUT cells were determined statistically significant using two tailed unpaired t-test (p = 0.05 and p = 0.0848, respectively). While differences between the leading and trailing edges within HET or MUT cells were also determined not statistically significant using two tailed paired t-test (p = 0.219 and p = 0.355). (H) The size of focal adhesions had an mean size ± SEM of 2.14±0.27 micrometer in HET and 3.09±0.3 micrometer in MUT cells. This difference in focal adhesion size was determined to be very statically significant using two-tailed unpaired t-test (p = 0.0013). The mean size ± SEM of focal adhesions at the leading edge was 1.70±0.24 micrometer for HET and 3.03±0.3 micrometer for MUT, while at the trailing edge the mean size ± SEM was 2.57±0.26 micrometer for HET and 3.15±0.3 micrometer for MUT. The mean focal adhesion size at the leading edge between HET and MUT cells were determined to be very statistically significantly different using unpaired two tailed t-test (p-value = 0.0016). When comparing leading and trailing focal adhesion size within HET cells there is a statistically significant difference in mean size two-tailed paired t-test (p-value = 0.001). Comparing mean focal adhesion size between leading and trailing edges within MUT cells showed no statistically significant difference using two tailed paired t-test (p = 0.1325). White bar denotes 50 micrometer.