The Caenorhabditis elegans LIN-26 protein is required to specify and/or maintain all non-neuronal ectodermal cell fates.
The C. elegans gene lin-26, which encodes a presumptive zinc-finger transcription factor, is required for hypodermal cells to acquire their proper fates. Here we show that lin-26 is expressed not only in all hypodermal cells but also in all glial-like cells. During asymmetric cell divisions that generate a neuronal cell and a non-neuronal cell, LIN-26 protein is symmetrically segregated and then lost from the neuronal cell. Expression in glial-like cells (socket and sheath cells) is biologically important, as some of these neuronal support cells die or seem sometimes to be transformed to neuron-like cells in embryos homozygous for strong loss-of-function mutations. In addition, most of these glial-like cells are structurally and functionally defective in animals carrying the weak loss-of-function mutation lin-26(n156). lin-26 mutant phenotypes and expression patterns together suggest that lin-26 is required to specify and/or maintain the fates not only of hypodermal cells but also of all other non-neuronal ectodermal cells in C. elegans. We speculate that lin-26 acts by repressing the expression of neuronal-specific genes in non-neuronal cells.
Labouesse
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M
Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
Hartwieg
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E
Horvitz
H R
HR
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000196:embryology / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D002454:Cell Differentiation; D002455:Cell Division; D002470:Cell Survival; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004475:Ectoderm / Q000166:cytology; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D008856:Microscopy, Fluorescence; D009154:Mutation; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D016335:Zinc Fingers
D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D015801:Helminth Proteins; D014157:Transcription Factors; C090507:lin-26 protein, C elegans