Fig. 2.

Embryonic expression of miR-27b at E10.5. (A) Whole-mount in situ hybridization profile using an LNA probe specific to miR-27b indicates widespread expression in the limb buds (fl and hl) and in the tail bud, as well as the neural tube (nt) and heart (ht). It is also expressed in the somites (so) where myogenesis is initiated. (B and C) Transverse sections of an immature caudal (B) and more mature interlimb (C) somites from A show that miR-27b is not expressed in the dermomyotome (dm) where Pax3-positive myogenic cells are present. It is present in the sclerotome (sc) of the immature somite and has accumulated in the myotome (m) (distinguished from the dermomyotome by a white dotted line). (D) A transverse section at interlimb level for an E10.5 embryo, after immunohistochemistry with a Myogenin (MyoG) antibody that marks differentiating muscle cells and a Pax3 antibody, marking progenitor cells in the dermomyotome, strongly labeled for miR-27b in the epaxial (e) and hypaxial lips, as well as interspersed cells in the myotome.