Induction of Ascidian Peripheral Neuron by Vegetal Blastomeres

Developmental Biology

Takashi Obinata¹  Yasushi Okamura¹  Yukio Ohtsuka¹ 

[1]Molecular Neurobiology Group, Neuroscience Research Institute, AIST, Tsukuba Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan

关键词: gelsolin;    epidermal sensory neuron;    neural induction;    cell-cell interaction;    bFGF;    neural crest;    placode;   

DOI  :  10.1006/dbio.2001.0425

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Ascidiantadpolelarvaehaveasimilardorsaltubularnervoussystemasvertebrates.Theinductionofbrainformationfroma4.2-derived(a-line)cellsrequiressignalsfromtheA4.1-derived(A-line)cells.However,littleisknownaboutthemechanismunderlyingthedevelopmentofthelarvalperipheralnervoussystemduetothelackofasuitablemolecularmarker.Gelsolin,anactin-bindingprotein,isspecificallyexpressedinepidermalsensoryneurons(ESNs)thatmainlyconstitutetheentireperipheralnervoussystemoftheascidianyoungtadpoles.Here,weaddresstheroleofcellinteractionsinthespecificationofESNsusingimmunostainingwithananti-gelsolinantibody.Animalhalf(a4.2-andb4.2-derived)embryosdidnotgiverisetoanygelsolin-positiveneurons,indicatingthatdifferentiationofESNsrequiressignalsfromvegetalcells.CellisolationexperimentsshowedthatA4.1blastomeresinducegelsolin-positiveneuronsfroma-linecellsbutnotfromb4.2-derived(b-line)cells.Ontheotherhand,B4.1blastomeresinducegelsolin-positiveneuronsbothfromb-linecellsanda-linecells.ThisisinsharpcontrasttothespecificationofbraincellswhichisnotaffectedbytheablationofB4.1-derived(B-line)cells.Furthermore,basicfibroblastgrowthfactor(bFGF)inducedESNsfromthea-linecellsandb-linecellsintheabsenceofvegetalcells.TheircompetencetoformESNswaslostbetweenthe110-cellstageandtheneurulastage.Ourresultssuggestedthatthespecificationofthea-linecellsandb-linecellsintoESNsiscontrolledbydistinctinducingsignalsfromtheanteriorandposteriorvegetalblastomeres.ESNsinthetrunkappeartobederivedfromthea8.26blastomeresaligningontheedgeofpresumptiveneuralregionwhereascidianhomologueofPax3isexpressed.ThesefindingshighlighttheclosesimilarityofascidianESNsdevelopmentwiththatofvertebrateplacodeandneuralcrest.

【 授权许可】

Unknown