Developmental Biology | |
Zebrafish Hox Paralogue Group 2 Genes Function Redundantly as Selector Genes to Pattern the Second Pharyngeal Arch | |
Victoria E. Prince1  Michael P. Hunter1  | |
[1] Department of Molecular Genetics and Cell Biology, The Committees on Developmental Biology, Genetics, Neurobiology and Evolutionary Biology, The University of Chicago, 1027 E. 57th Street, Chicago, Illinois, 60637 | |
关键词: zebrafish; Hox; hindbrain; pharyngeal arches; morpholino; knock-down; selector genes; redundancy; Meckel's cartilage; | |
DOI : 10.1006/dbio.2002.0701 | |
学科分类:生物科学(综合) | |
来源: Academic Press | |
【 摘 要 】
Thepharyngealarchesareoneofthedefiningfeaturesofthevertebrates,withthefirstarchformingthemandiblesofthejawandthesecondformingjawsupportstructures.Thecartilaginouselementsofeacharchareformedfromseparatemigratoryneuralcrestcellstreams,whichderivefromthedorsalaspectoftheneuraltube.ThesecondandmoreposteriorcreststreamsarecharacterizedbyspecificHoxgeneexpression.ThezebrafishhasalargeroverallnumberofHoxgenesthanthetetrapodvertebrates,astheresultofaduplicationeventinitslineage.However,inbothzebrafishandmouse,therearejusttwomembersofHoxparaloguegroup2(PG2):Hoxa2andHoxb2.Here,weshowthatmorpholino-mediated“knock-downâ€ofbothzebrafishHoxPG2genesresultsinmajordefectsinsecondpharyngealarchcartilages,involvingreplacementofventralelementswithamirror-imageduplicationoffirstarchstructures,andaccompanyingchangestopharyngealmusculature.Inthemouse,nullmutantsofHoxa2haverevealedthatthissingleHoxgeneisrequiredfornormalsecondarchpatterning.Bycontrast,loss-of-functionofeitherzebrafishHoxPG2geneindividuallyhasnophenotypicconsequence,showingthatthesetwogenesfunctionredundantlytoconferproperpatterntothesecondpharyngealarch.Wehavealsousedhoxb1amis-expressiontoinducelocalizedectopicexpressionofzebrafishHoxPG2genesinthefirstarch;usingthisstrategy,wefindthatectopicexpressionofeitherHoxPG2genecanconfersecondarchidentityontofirstarchstructures,suggestingthatthezebrafishHoxPG2genesactas“selectorgenes.â€
【 授权许可】
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