Xenopus Enhancer of Zeste (XEZ); an anteriorly restricted polycomb gene with a role in neural patterning.
We have identified the Xenopus homologue of Drosophila Enhancer of Zeste using a differential display strategy designed to identify genes involved in early anterior neural differentiation. XEZ codes for a protein of 748 amino acids that is very highly conserved in evolution and is 96% identical to both human and mouse EZ(H)2. In common with most other Xenopus Pc-G genes and unlike mammalian Pc-G genes, XEZ is anteriorly restricted. Zygotic expression of XEZ commences during gastrulation, much earlier than other anteriorly localized Pc-G genes; expression is restricted to the anterior neural plate and is confined later to the forebrain, eyes and branchial arches. XEZ is induced in animal caps overexpressing noggin; up-regulation of XEZ therefore represents a response to inhibition of BMP signalling in ectodermal cells. We show that the midbrain/hindbrain junction marker En-2,and hindbrain marker Krox-20, are target genes of XEZ and that XEZ functions to repress these anteroposterior marker genes. Conversely, XEZ does not repress the forebrain marker Otx-2. XEZ overexpression results in a greatly thickened floor of the forebrain. These results implicate an important role for XEZ in the patterning of the nervous system.
Barnett
M W
MW
Cell and Molecular Development Group, Department of Biological Sciences, University of Warwick, CV4 7AL, Coventry, UK.
Seville
R A
RA
Nijjar
S
S
Old
R W
RW
Jones
E A
EA
D000595:Amino Acid Sequence; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002352:Carrier Proteins; D002454:Cell Differentiation; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000378:metabolism; D029721:Drosophila Proteins; D004475:Ectoderm / Q000378:metabolism; D000071221:Enhancer of Zeste Homolog 2 Protein; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D015723:Gene Library; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D009924:Organ Culture Techniques; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D016548:Prosencephalon / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation; D014981:Xenopus; D029867:Xenopus Proteins; D000099176:Noggin Protein
D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D000071221:Enhancer of Zeste Homolog 2 Protein; D009687:Nuclear Proteins; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D011506:Proteins; D012313:RNA; D012333:RNA, Messenger; D012097:Repressor Proteins; D029867:Xenopus Proteins; D000099176:Noggin Protein; C083329:E(z) protein, Drosophila; C583224:EZH2 protein, Xenopus