cash4, a novel achaete-scute homolog induced by Hensen's node during generation of the posterior nervous system.
In vertebrate embryos, the precursor cells of the central nervous system (CNS) are induced by signaling from the organizer region. Here we report the isolation of a novel vertebrate achaete-scute homolog, cash4, which is expressed in the presumptive posterior nervous system in response to such signaling. cash4 is first expressed in epiblast cells flanking the late-phase organizer (Hensen's node), which retains its ability to induce cash4 during regression to the caudal end of the embryo. We show that these node-derived signals can be mimicked in vivo by the activity of fibroblast growth factor (FGF). We demonstrate that cash4 can substitute for the achaete/scute genes in the fly and that it also has proneural activity in vertebrate embryos. Together these results suggest that cash4 functions as a proneural gene downstream of node-derived signals (including FGF) to promote the formation of the neural precursors that will give rise to the posterior CNS in the chick embryo.
Henrique
D
D
Developmental Genetics, Imperial Cancer Research Fund, London, UK.
Tyler
D
D
Kintner
C
C
Heath
J K
JK
Lewis
J H
JH
Ish-Horowicz
D
D
Storey
K G
KG
D000595:Amino Acid Sequence; D000663:Amphibians / Q000196:embryology / Q000235:genetics; D000818:Animals; D030161:Avian Proteins; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000235:genetics; D002490:Central Nervous System / Q000196:embryology*; D002642:Chick Embryo / Q000166:cytology / Q000502:physiology*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000502:physiology; D004627:Embryonic Induction / Q000235:genetics; D005314:Embryonic and Fetal Development / Q000235:genetics; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
D030161:Avian Proteins; D051792:Basic Helix-Loop-Helix Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005346:Fibroblast Growth Factors; D011994:Recombinant Proteins; D014157:Transcription Factors; C099107:CASH-1 protein, Gallus gallus; C105240:CASH4 protein, Gallus gallus; C089199:ac protein, Drosophila; C089197:sc protein, Drosophila