Table 1.
Regulation of BMP modulators.
Figure 1.
In situ hybridizations in longitudinal (A–G, M–P) and transverse (H–L; Q–T) vibratome sections of the autopod showing the expression of Noggin (A), Chd (B), Chdl-1 (C), Chdl-2 (D), Tsg (E and I), Dan (F and J), BMPER (G and K), Sost (H), Sostdc1 (L), Tll1 (M and Q), Fst (N and R), Fstl-1 (O and S), and Fstl-5 (P and T).
All the specimens are at day 6,5 of incubation (stage 30HH) except H, which is at 7,5 days of incubation (stage 32HH).
Figure 2.
In situ hybridization on transverse sections of the proximal segment of the autopod of embryos after 7 and 7,5 days of incubation, to show the expression domains of BMP modulators in the zone of hypertrophic differentiation of the metatarsal and in the maturing tendons at the zone close to the myotendinous junction.
Noggin (A), Fstl- 5 (B), Chd (C), BMPER (D), Chdl-2 (E), Sost (F), Tll1 (G), and Tsg (H). Note that at this stage of differentiation Tll1 transcripts are present in the tendon blastemas (arrow heads in G). Note also that the expression domains in the diaphysis of the metatarsal are specifically located in the inner cellular layer of the perichondrium in the interface with the hypertrophic cartilage.
Figure 3.
Immunolabeling for p-Smad 1/5/8 (green, A–D) and p-c-Jun (green, E), to show the zones of active BMP signaling in the course of digit formation.
Note in A, the absence of labeling in the tendon blastema (tb) at 7,5 days of incubation. In addition, zones of intense labeling paralleling the expression of BMPER of are observed, (arrows, compared with Fig. 1K). B is a higher magnification image of A to show the labeling in the differentiating cartilage except in the most peripheral region subjacent to the perichondrium (p). C shows positive labeling in a proximal region of the tendons corresponding with the myotendinous junction (day 8 of incubation). D is a longitudinal section of digit 3 at day 6 of incubation showing intense labeling in the growing tip (dt) and reduced labeling in the zones of joint formation (arrow heads). E, is a longitudinal section of digit 3, showing intense labeling for p-c-Jun in the joint forming region (arrow heads). In A and B the actin cytoskeleton was labeled in red with Phalloidin-TRITC. F–M, are longitudinal (F, G, I, K, and M) and transverse (H, J, and L) sections through digit 3 showing the expression of type 1 BMP receptors in the autopod. Bmpr1b (F–H) is highly expressed at RNA (F–H) and protein (G) levels in the early chondrogenic digit ray with zones of reduced expression in the joint forming region. In the non-chondrogenic domains of the autopod, the expression of Bmpr1b is predominant in the subectodermal mesenchyme and interdigital regions. Expression of Bmpr1a (I–J) and Alk2 (K–L) is poor in the chondrogenic rays, but transcripts are abundant in the tissues around the digit cartilage including the perichondrium, the interdigital mesenchyme. Transcripts of Alk2, are also appreciated in the developing joints (arrow in K). Alk 1 was only appreciated in the peridigital blood vessels (M).
Table 2.
Regulation of Cartilage Markers.
Table 3.
Regulation of Joint Markers.
Table 4.
Regulation of Tendon Markers.
Table 5.
Regulation of BMP modulators.
Table 6.
Semi-quantitative association of gene expression intensity in the autopodial tissues.