Balancing cell numbers during organogenesis: Six1a differentially affects neurons and sensory hair cells in the inner ear

摘要

Whilegenesinvolvedinthedifferentiationofthemechanosensoryhaircellsandtheneuronsinnervatingthemhavebeenidentified,genesinvolvedinbalancingtheirrelativenumbersremainunknown.Six1aplaysadualrolebypromotinghaircellfatewhileinhibitingneuronalfateinthesetwolineages.Geneshomologoustosix1aactaseithertranscriptionalactivatorsorrepressors,dependingonthepartnerswithwhichtheyinteract.Byassayingtheinvivoandinvitroeffectsofmutationsinpresumptiveprotein-proteininteractingandDNA-bindingdomainsofSix1a,weshowthat,inthedevelopingzebrafishinnerear,Six1apromoteshaircellfatebyactingasatranscriptionalactivatorandinhibitsneuronalfatebyactingasatranscriptionalrepressor.WealsoidentifyseveralpotentialpartnersforSix1athatdifferbetweenthesetwolineages.ThedualroleofSix1ainthedevelopingotocystprovidesamechanismforbalancingtherelativenumberofhaircellsandneuronsduringorganogenesisoftheinnerear./p/div