title: Mammalian achaete-scute homolog 1 is transiently expressed by spatially restricted subsets of early neuroepithelial and neural crest cells.
abstract: Using monoclonal antibodies, we have examined the expression pattern of MASH1, a basic helix-loop-helix protein that is a mammalian homolog of the Drosophila achaete-scute proteins. In Drosophila, achaete-scute genes are required for the determination of a subset of neurons. In the rat embryo, MASH1 expression is confined to subpopulations of neural precursor cells. The induction of MASH1 precedes, but is extinguished upon, overt neuronal differentiation. MASH1 is expressed in the forebrain by spatially restricted domains of neuroepithelium and in the peripheral nervous system exclusively by precursors of sympathetic and enteric neurons. The features of early and transient expression, in spatially restricted subpopulations of neural precursors, are similar to those observed for achaete-scute. Thus, the amino acid sequence conservation between MASH1 and achaete-scute is reflected in a parallel conservation of cell type specificity of expression, similar to the case of mammalian MyoD and Drosophila nautilus. These data support the idea that helix-loop-helix proteins may represent an evolutionarily conserved family of cell-type determination genes, of which MASH1 is the first neural-specific member identified in vertebrates.
authors.affiliation: Howard Hughes Medical Institute, California Institute of Technology, Pasadena 91125.
authors.forename: L C
authors.initials: LC
authors.lastname: Lo
authors.forename: J E
authors.initials: JE
authors.lastname: Johnson
authors.forename: C W
authors.initials: CW
authors.lastname: Wuenschell
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.forename: D J
authors.initials: DJ
authors.lastname: Anderson
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000302:isolation & purification; D000918:Antibody Specificity; D051792:Basic Helix-Loop-Helix Proteins; D005075:Biological Evolution; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics; D004622:Embryo, Mammalian / Q000378:metabolism; D004625:Embryo, Nonmammalian; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D015870:Gene Expression; D007150:Immunohistochemistry; D051379:Mice; D009420:Nervous System / Q000196:embryology / Q000378:metabolism; D009432:Neural Crest / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013564:Sympathetic Nervous System / Q000166:cytology; D014157:Transcription Factors
chemical_list: D000911:Antibodies, Monoclonal; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C499317:Ascl1 protein, mouse; C499318:Ascl1 protein, rat