Jagged1 peptide appearing in mandibular condylar cartilage development

We investigated the expression pattern of Jagged1 peptide in mandibular condylar cartilage, as a type of secondary cartilage. Mandibular condyle of ddY mice were fixed from embryonic day 15 (E15) through just after birth (equivalent to E19). Serial sections were examined using histological immunohistochemical (IHC) techniques. At E15, the proliferating cells had positive products of Jagged1 in their cytoplasms and cell membrane of almost all coagulating cells. At E17, cytoplasmic and membranuous reactions of Jagged1 factors appeared strongly in the cells just inside the condylar cartilage sheath. At E18, Jagged1 positive products were observed in almost all cells of the layers, and they were mostly distinct in the sheath of the condyle. At just after birth, Jagged1 was observed in a portion of almost all layer cells in their cytoplasm and membrane. These results suggest that Jagged1 plays an essential role for mandibular condylar cartilage morphogenesis and development.