Fig. 4.

Fgfr2b expression is critical for Steno's gland, MSG, LNG 4 and MNG development. (A–B) The MSG develops from the maxillary sinus epithelium in WTs however fails to develop in Fgfr2b deficient mice. (C) The distal LNG2 and Steno's gland develop in WT animals. (D) The Steno's gland is completely absent in Fgfr2b−/− mice. LNG2 is found in Fgfr2b−/− animals however branching of the gland is reduced (D). (E) A branched LNG3 has developed by E18.5 in WT animals. (F) The LNG3 duct extends to the same location in Fgfr2b−/− mice however branching of the distal gland is reduced. (G–H) Both LNG4 glands are found below the nasal cartilage capsule in WT animals, however are completely absent with the loss of Fgfr2b. (I–J) The MNGs are completely absent in Fgfr2b−/− mice compared to their WT littermates, indicated by absence of the MNG ducts. Scale bar=100 µm.