Identification of candidate secreted factors involved in trigeminal placode induction.
Cranial ectodermal placodes are critical for normal development of the peripheral nervous system of the head. However, many aspects of the molecular and tissue interactions involved in their induction have yet to be elucidated. The trigeminal placode is induced by an unidentified secreted factor(s) from the dorsal neural tube. To determine candidates that may be involved in this induction process, we have performed reverse transcriptase-polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization to screen for receptors expressed by uninduced presumptive trigeminal level ectoderm. We have found that receptors for fibroblast growth factors, insulin-like growth factors, platelet-derived growth factors, Sonic hedgehog, the transforming growth factor-beta superfamily, and Wnts all are expressed in patterns consistent with a role in trigeminal placode formation. This RT-PCR screen for candidate receptors expressed in presumptive trigeminal ectoderm is the first systematic screen to identify potential interactions underlying induction of the trigeminal placode and represents a critical step for understanding this complex process.
McCabe
Kathryn L
KL
Division of Biology MC 139-74, California Institute of Technology, Pasadena, California 91125, USA.
Shiau
Celia E
CE
Bronner-Fraser
Marianne
M
D000818:Animals; D002645:Chickens; D004475:Ectoderm / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D047108:Embryonic Development; D004627:Embryonic Induction; D051157:Frizzled Receptors / Q000378:metabolism; D000072079:Patched Receptors; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D017978:Receptors, Growth Factor / Q000378:metabolism*; D017451:Receptors, Somatomedin / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012668:Trigeminal Ganglion / Q000196:embryology*
D051157:Frizzled Receptors; D000072079:Patched Receptors; D011956:Receptors, Cell Surface; D017468:Receptors, Fibroblast Growth Factor; D017978:Receptors, Growth Factor; D017451:Receptors, Somatomedin; D018125:Receptors, Transforming Growth Factor beta