BMP4 and coloboma: Jnk1−/− Jnk2−/+ mice (lacking activity of members of the Jun N-terminal Kinase, JNK, group of mitogen activated kinases) exhibit coloboma associated with loss of Shh and Bmp4 signaling, and reduced levels of Pax2, while addition of Bmp4 restored Shh and Pax2 expression (39).