Transcriptional Integration of Competence Modulated by Mutual Repression Generates Cell-Type Specificity within the Cardiogenic Mesoderm

Developmental Biology

Mingtsan Su¹  Miki Fujioka¹  Margaret Liu¹  James B. Jaynes¹  Zhe Han¹  Rolf Bodmer¹ 

[1] Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, 48109

关键词: even-skipped;    heart;    cell fate;    tinman;    ladybird;    wingless;    TGF-β;    repression;   

DOI  :  10.1006/dbio.2002.0846

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Thewayinwhichspatiallypatternedcellularidentitiesaregeneratedisacentralquestionoforganogenesis.InthecaseofDrosophilaheartformation,thecardiacprogenitorsarespecifiedinprecisemesodermalpositions,givingrisetomultiplecelltypesinahighlyorderedarrangement.Here,westudythemechanismsbywhichpositionalinformationconveyedbysignalingpathwaysandacombinatorialcodeofactivatingandrepressingtranscriptionfactorsworktogethertoconfinetheexpressionofthehomeoboxgeneeven-skipped(eve)toasmallregionofthedorsalmesoderm.Bymanipulatingbothexpressionpatternsandbindingsitesfortranscriptionfactors,weshowthatacomplexcombinationofregulatoryactivitiesconvergeonasingleenhancerofevetogeneratepreciselytargetedgeneexpressionwithinthecardiacmesoderm.Inparticular,ladybirdearly(lbe),ahomeoboxgeneexpressedadjacenttoeve,restrictsthepositiveactionsoffactorsdownstreamofwingless,decapentaplegic,andrastogeneratetheevepattern.MutationofaLbebindingsitecausesdramaticexpansionofexpressionandabolishestheresponsivenesstorepressionbylbe.Conversely,eliminatingeveinthemesodermexpandslbeexpressionintothenormaleve-expressingterritory,suggestingthatmutualrepressionbetweeneveandlbeisessentialfordelineatingthespatialpatternsofgeneexpressionthatspecifycelltypeswithinthecardiacmesoderm.

【 授权许可】

Unknown