Cranial Neural Crest Cells Contribute to Connective Tissue in Cranial Muscles in the Anuran Amphibian, Bombina orientalis

摘要

Thecontributionofcranialneuralcrestcellstothedevelopmentandpatterningofcranialmusclesinamphibianswasinvestigatedinthephylogeneticallybasalandmorphologicallygeneralizedfrog,Bombinaorientalis.Experimentalmethodsincludedfluorescentmarkingofpremigratorycranialneuralcrestandextirpationofindividualmigratorystreams.Neuralcrestcellscontributedtotheconnectivetissuecomponent,butnotthemyofibers,ofmanylarvalmuscleswithinthefirsttwobranchialarches(mandibularandhyoid),andcomplexchangesinmusclepatterningfollowedneuralcrestextirpation.Connectivetissuecomponentsofindividualmusclesofeitherarchoriginatefromtheparticularcrestmigratorystreamthatisassociatedwiththatarch,andthisrelationshipismaintainedregardlessofthesegmentalidentitya€”orembryonicderivationa€”ofassociatedskeletalcomponents.Thesedevelopmentalrelationsdefineapatternofsegmentationintheheadoflarvalanuransthatissimilartothatpreviouslydescribedinthedomesticchicken,theonlyvertebratethathasbeenthoroughlyinvestigatedinthisrespect.Thefundamentalroleoftheneuralcrestinpatterningskeletonandmusculaturemayrepresentaprimitivefeatureofcranialdevelopmentinvertebrates.Moreover,thecorrespondingdevelopmentalprocessesandcellfatesappeartobeconservedevenwhenmajorevolutionaryinnovationsa€”suchasthenovelcartilagesandmusclesofanuranlarvaea€”resultinmajordifferencesincranialform.