TGFbeta ligands promote the initiation of retinal ganglion cell dendrites in vitro and in vivo.
Each type of neuron develops a unique morphology critical to its function, but almost all start with the basic plan of one long axon and multiple short, branched dendrites. Though extrinsic signals are known to direct many steps in the development of neuronal structure, little is understood about the initiation of processes, particularly dendrites. We find that Xenopus retinal ganglion cells (RGCs) explanted early will extend axons and not dendrites in dissociated cultures. If RGCs develop longer in vivo prior to culturing, many now extend dendrite-like processes in vitro, suggesting that an extrinsic factor is required to stimulate dendrite initiation. Members of the transforming growth factor beta (TGFbeta) superfamily, bone morphogenetic protein 2 (BMP2), and growth and differentiation factor 11 (GDF11), can signal cultured RGCs to form dendrites. Furthermore, TGFbeta ligands have an endogenous role: blocking BMP/GDF signaling with a secreted antagonist or inhibitory receptors reduces the number of primary dendrites extended in vivo.
Hocking
Jennifer C
JC
Hotchkiss Brain Institute, University of Calgary, HSC Rm. 2207, 3330 Hospital Dr., NW, Calgary, AB, Canada T2N 4N1.
Hehr
Carrie L
CL
Chang
Ruoh-Yeng
RY
Johnston
Jillian
J
McFarlane
Sarah
S
D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003712:Dendrites / Q000187:drug effects / Q000648:ultrastructure*; D005260:Female; D055412:Growth Differentiation Factors; D009865:Oocytes; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism; D014982:Xenopus laevis
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; C492266:GDF11 protein, human; D055412:Growth Differentiation Factors; D016212:Transforming Growth Factor beta