DEV01822 Supplementary Material

Files in this Data Supplement:

• Supplemental Figure 1 -

  Fig. S1. Phenotypic defects in the thoracic region of Tsg^–/–;Bmp7^–/– and Tsg^+/–;Bmp7^–/– neonate skeletons stained with Alcian Blue (cartilage) and Alizarin Red (bone). (A and B) View of the vertebral bodies showing the presence of two ossification centers in the Tsg;Bmp7 double mutant instead of the normal single one (white arrow). (C-F) Ventral view of the sternum of wild-type, Bmp7^–/–;Tsg^–/– and Tsg or Bmp7 single mutants. Numbers I to VI designate the sternebrae and numbers 1 through 7 the ribs. Note that Bmp7^–/– mutants often lack the fifth sternebra (asterisk in panel E) (Dudley et al., 1995) while in the Tsg^–/–;Bmp7^–/– mutant the fourth and fifth sternebrae are incomplete or missing (bracket in panel F). In the Tsg^–/–;Bmp7^–/– mutant the fourth, fifth, and sixth ribs are fused to each other (black arrow). These results showed that in the spinal column of the compound mutant the vertebral bodies were smaller, ossification was delayed and chondrogenesis was incomplete in the region of the centrum, with the formation of two ossification centers instead of a single central one in compound mutants (panels A,B). Since Bmps are well-known inducers of chondrogenesis, the defects observed in the Tsg^–/–;Bmp7^–/– mutant are consistent with a role for Tsg in promoting Bmp activity. The sternum of Tsg^–/– pups was unaffected (panels 1D), but much more severe additional defects were observed in Tsg^–/–;Bmp7^–/– rib cages (panel F).

• Supplemental Figure 2 -

  Fig. S2. Anatomical analysis of the siren phenotype. Serial transverse histological sections of the posterior region of wild-type, Tsg^–/–;Bmp7^–/–, Bmp7^–/– and Tsg^+/–;Bmp7^–/– embryos. Hematoxylin and Eosin staining.