Lack of tailless leads to an increase in expression variability in Drosophila embryos

摘要

Developmentalprocessesarerobust,orcanalised:dynamicpatternsofgeneexpressionacrossspaceandtimeareregulatedreliablyandpreciselyinthepresenceofgeneticandenvironmentalperturbations.Itremainsunclearwhethercanalisationreliesonspecificregulatoryfactors(suchasheat-shockproteins),orwhetheritisbasedonmoregeneralredundancyanddistributedrobustnessatthenetworklevel.Thelatterexplanationimpliesthatmutationsinmanyregulatoryfactorsshouldexhibitlossofcanalisation.Here,wepresentaquantitativecharacterisationofsegmentationgeneexpressionpatternsinmutantsoftheterminalgapgeneemtailless/em(emtll/em)inemDrosophilamelanogaster/em.Ouranalysisprovidesnewinsightsintothedynamicmechanismsunderlyinggapgeneregulation,andrevealssignificantlyincreasedvariabilityofgeneexpressioninthemutantcomparedtothewild-typebackground.Weshowthatbothpositionandtimingofposteriorsegmentationgeneexpressiondomainsvarystronglyfromembryo-to-embryoinemtll/emmutants.Thisvariabilitymustbecausedbyavulnerabilityintheregulatorysystemwhichishiddenorbufferedinthewild-type,butbecomesuncoveredbythedeletionofemtll/em.Ouranalysisprovidesevidencethatlossofcanalisationinmutantscouldbemorewidespreadthanpreviouslythought./p/div