Figure 4. Laminin distribution in the myotomal basement membrane. (A) Cartoon showing the expression pattern of Lama1 (red) and Lama5 (green) in interlimb somites. Different shades of red indicate low and high levels of expression. Lama1 is expressed in the sclerotome, ventral neural tube and promesonephros. Lama5 is expressed in the dorsal medial lip of the dermomyotome, notochord, ventral neural tube and promesonephros. (B) Laminin α1 distribution in mouse interlimb somites. The myotomal basement membrane (white arrows) deposited at the interface between myotomal (Myf5-expressing cells in blue) and sclerotomal cells contains laminin α1 (green). The dermomyotome is labeled with Pax3 (red). Note the absence of laminin α1 in the BM surrounding the notochord. (C) Laminin α5 distribution in mouse interlimb somites. The myotomal basement membrane (white arrows) deposited at the interface between myotomal (myogenin-expressing cells in red) and sclerotomal cells contains laminin α5 (green). Note the presence of laminin α5 in the BM surrounding the notochord.