Emx3 is required for the differentiation of dorsal telencephalic neurons.
emx3 is first expressed in prospective telencephalic cells at the anterior border of the zebrafish neural plate. Knockdown of Emx3 function by morpholino reduces the expression of markers specific to dorsal telencephalon, and impairs axon tract formation. Rescue of both early and late markers requires low-level expression of emx3 at the one- or two-somite stage. Higher emx3 expression levels cause dorsal telencephalic markers to expand ventrally, which points to a possible role of emx3 in specifying dorsal telencephalon and a potential new function for Wnt/beta-catenin pathway activation. In contrast to mice, where Emx2 plays a major role in dorsal telencephalic development, knockdown of zebrafish Emx2 apparently does not affect telencephalic development. Similarly, Emx1 knockdown has little effect. Previously, emx3 was thought to be fish-specific. However, we found all three emx orthologs in Xenopus tropicalis and opossum (Monodelphis domestica) genomes, indicating that emx3 was present in an ancestral tetrapod genome.
Viktorin
Gudrun
G
Institute of Developmental Biology, University of Freiburg, Freiburg, Germany.
Chiuchitu
Christina
C
Rissler
Michael
M
Varga
Zoltán M
ZM
Westerfield
Monte
M
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000648:ultrastructure; D001483:Base Sequence; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013687:Telencephalon / Q000166:cytology / Q000196:embryology*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D051153:Wnt Proteins / Q000235:genetics / Q000502:physiology; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000502:physiology*; D029961:Zebrafish Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D051176:beta Catenin / Q000235:genetics / Q000502:physiology; D000099260:Empty Spiracles Homeobox Proteins
D018398:Homeodomain Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; D014157:Transcription Factors; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin; D000099260:Empty Spiracles Homeobox Proteins; C495269:ctnnb1 protein, zebrafish