Nov expression and phenotype of subcutaneous and hypaxial muscles. A: RNA in situ hybridization showing Nov expression in subcutaneous (arrow head), body wall (filled arrow) and intervertebral muscles (arrow) in E16.5 embryos. B, C: photographs of wild type (B) and Novdel3-/- (C) body walls, showing thinning and transparency in the mutant. D-I: Haematoxylin and Eosin stained sections of adult skin from wild type (D, G), Novdel3+/- (E, H) and Novdel3-/- (F, I) mice showing atrophy of subcutaneous muscles in Novdel3+/- and Novdel3-/- mice, with arrow heads marking the residual muscle layer. Histology of the subcutaneous adipose tissue in wild type (J) and Novdel3-/- (K) showing large mature fat cells in the wild type in contrast to the mixture of large (mature) and small (immature) fat cells in the mutant. L, M: Haematoxylin and Eosin stained section of adult intercostal muscles in wild type (L) and Novdel3-/- (M) mice showing muscle atrophy and transdifferentiation to fat in the mutant. Scale bars in A = 20 μm; D-F = 50 μm; G-M = 10 μm.