FIG. 5.

LacZ-positive cells in islet-1 nlacZ knock-in mouse model. (a–d) LacZ-positive cells are located around the outflow tract in a 12-week-old islet-1 nlacZ knock-in mouse. (b–d) Serial sections showing magnifications of the insets delineated by small (b, c) or large (d) squares in a. Cells are arranged in a cluster (b, hematoxylin–eosin staining); some of them express islet-1 in the nucleus (c, X-gal staining), and they are α-actinin negative (d). Asterisks indicate similar areas in b–d; arrows point out remote cardiac areas positive for α-actinin in d. (e–g) Adjacent sections showing a cluster located in RA, containing cells expressing islet-1 in the nucleus (e), nlacZ (f, pointed by arrows), and/or acetylcholinesterase (f), but no sarcomeric structures (g, phalloidin staining). Scale bars: (a) 800 μm; (b, c) 100 μm; (d) 200 μm; (e–g) 75 μm. Color images available online at www.liebertonline.com/scd