Saltatory control of isometric growth in the zebrafish caudal fin is disrupted in long fin and rapunzel mutants

摘要

Zebrafishfinsgrowbysequentiallyaddingnewsegmentsofbonetothedistalendofeachfinray.Inwildtypezebrafish,segmentadditionisregulatedsuchthatanisometricrelationshipismaintainedbetweenfinlengthandbodylengthoverthelifespanofthegrowingfish.Usinganovel,surrogatemarkerforfingrowthinconjunctionwithcellproliferationassays,wedemonstrateherethatsegmentadditionisnotcontinuous,butratherproceedsbysaltation.Saltationisafundamentalgrowthmechanismsharedbydisparatevertebrates,includinghumans.Wefurtherdemonstratethatsegmentadditionproceedsinconjunctionwithcyclicburstsofcellproliferationinthedistalfinraymesenchyme.Incontrast,cellsinthedistalfinepidermisproliferateataconstantratethroughoutthefinraygrowthcycle.Finally,weshowthattwoseparatefinovergrowthmutants,emlongfin/emandemrapunzel,/embypassthestasisphaseofthefinraygrowthcycletodevelopasymmetricalandsymmetricalfinovergrowth,respectively./p/div