Developmental Biology | |
Hemangioblast Commitment in the Avian Allantois: Cellular and Molecular Aspects | |
F. Dieterlen-Lièvre1  T. Jaffredo1  A. Caprioli1  C. Drevon1  K. Minko1  A. Eichmann1  | |
[1] Institut d'Embryologie Cellulaire et Moléculaire du CNRS et du Collège de France, 49 bis av. de la Belle Gabrielle, 94736, Nogent s/Marne Cedex, France | |
关键词: hemangioblasts; hemopoiesis; allantois; avian embryo; GATA factors; VEGF-R2; SCL/tal-1; | |
DOI : 10.1006/dbio.2001.0362 | |
学科分类:生物科学(综合) | |
来源: Academic Press | |
【 摘 要 】
Werecentlyidentifiedtheallantoisasasiteproducinghemopoieticandendothelialcellscapableofcolonizingthebonemarrowofanengraftedhost.Here,wereportadetailedinvestigationofsomeearlycytologicalandmolecularprocessesoccurringintheallantoicbud,whichareprobablyinvolvedintheproductionofangioblastsandhemopoieticcells.Weshowthattheallantoisundergoesaprogramcharacterizedbytheprominentexpressionofseveral“hemangioblasticâ€genesinthemesodermaccompaniedbyothergenepatternsintheassociatedendoderm.VEGF-R2,atleastfromstageHH17onward,isexpressedandisshortlyfollowedbytranscriptionfactorsGATA-2,SCL/tal-1,andGATA-1.Bloodisland-likestructuresdifferentiatethatcontainbothCD45+cellsandcellsaccumulatinghemoglobin;thesestructureslookexactlylikebloodislandsintheyolksac.Thishemopoieticprocesstakesplacebeforetheestablishmentofavascularnetworkconnectingtheallantoistotheembryo.Asfarastheendodermisconcerned,GATA-3mRNAisfoundintheregionwhereallantoiswilldifferentiatebeforetheposteriorinstestinalportalbecomesanatomicallydistinct.Shortlybeforethebudgrowsout,GATA-2wasexpressedintheendodermand,atthesametime,thehemangioblasticprogrambecameinitiatedinthemesoderm.GATA-3isdetectedatleastuntilE8andGATA-2untilE3thelateststageexaminedforthisfactor.Usinginvitrocultures,weshowthatallantoicbuds,dissectedoutbeforetheestablishmentofcirculationbetweenthebudandtherestoftheembryo,producederythrocytesofthedefinitivelineage.Moreover,usingheterospecificgraftsbetweenchickandquailembryos,wedemonstratethattheallantoicvascularnetworkdevelopsfromintrinsicprogenitors.Takentogether,theseresultsextendourearlierfindingsaboutthecommitmentofmesodermtotheendothelialandhemopoieticlineagesintheallantois.ThedetectionofaprominentGATA-3expressionrestrictedtotheendodermofthepreallantoicregionandallantoicbud,followedbythatofGATA-2,isaninterestingandnovelinformation,inthecontextoforganformationandendodermspecificationintheemergenceofhemopoieticcells.
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