Figure 2: Early and transient Shh expression is sufficient for pattern specification in the genital tubercle.
From: Sonic hedgehog controls growth of external genitalia by regulating cell cycle kinetics
(a, b) Whole mount in situ hybridizations showing gene expression patterns in genital tubercles of ShhcreERT2/C and control Shh+/c mice. Genital tubercles are shown in ventral view, except where indicated. Shh was inactivated by tamoxifen injection at E10.5, immediately after initiation of tubercle outgrowth, and embryos were collected at E12.5 (Bmp4, and Msx2) or E13.5 (Wnt5a, Hoxd13, Hoxa13, Bmp7). Genital tubercles are reduced in size but show normal spatial expression patterns except for absence of Bmp7 expression in preputial glands (red arrow in b). Black arrows mark regionalized gene expression domains. Enlargement (red box) shows Bmp7-expressing preputial gland cells in control littermate. (c, d) qRT–PCR data for genes shown in (a) and (b). Embryos were injected with tamoxifen at E10.5 and collected at E12.5 (c), and injected at E11.5 and collected at E13.5 (d). Transcript levels expressed as percentage relative to control littermates, with n=3 for each data point. Error bars show ± s.e.m. and asterisks denote significant differences in (c) Msx2 (P=0.009) and (d) Msx2 (P=0.013), Bmp4 (P=0.002) and Bmp7 (P=0.010).
