Figure 9: Modest contribution of MECs to developing muscle via Cdh5^Cre lineage tracing.

(a) FACS analysis of VE-cadherin expression on MECs, SCs and APs via antibody staining. MECs were nearly all positive for VE-Cadherin, while the vast majority of SCs and APs were negative. (b) Detection of VE-cadherin-YFP expression in SCs and MECs using Cdh5^Cre:R26R^YFP mice. Again, SCs were all negative for VE-cadherin expression, while only ~40–50% of MECs were viewed as YFP positive, demonstrating an overall lower labelling yield of MECs when compared with the antibody staining. (c–g) Detection of β-gal-positive nuclei (blue) in tissue sections of trapezius muscles of Cdh5^Cre:R26^NZG mice. While most β-gal-positive nuclei were located between myofibres (black arrows), a very small proportion was also seen incorporated into myofibres (red arrows), as also documented by laminin co-staining (h, brown). (i–k) The same results were obtained for CTX-injured TA muscle.