title: The C. elegans Hox gene egl-5 is required for correct development of the hermaphrodite hindgut and for the response to rectal infection by Microbacterium nematophilum.
abstract: Members of the Hox gene family encode transcription factors that specify positional identity along the anterior-posterior axis of nearly all metazoans. One among the Caenorhabditis elegans Hox genes is egl-5. A deletion allele of egl-5 was isolated in a screen for animals which fail to develop swollen tails when exposed to the bacterial pathogen Microbacterium nematophilum. We show that compromised rectal development, which occurs as a result of loss of egl-5 function, results in a failure of rectal epithelial cells to express the ERK MAP kinase mpk-1, which was previously shown to mediate tail-swelling in response to bacterial infection. Tissue-specific rescue experiments demonstrated that egl-5 and mpk-1 act autonomously in rectal cells in the morphological response. The weak egl-5 allele (n1439), which does not compromise rectal development, fails to affect tail-swelling. We find that this allele carries an inserted repeat element approximately 13.8 kb upstream of the egl-5 open reading frame, which specifically disrupts the cell-specific expression of this gene in HSN egg-laying neurons. Together these findings extend the complexity of regulation and function of Hox genes in C. elegans and demonstrate the importance of their tissue-specific expression for correct development and response to infection.
authors.affiliation: School of Molecular and Microbial Biosciences, University of Sydney, NSW, Australia.
authors.forename: Hannah R
authors.initials: HR
authors.lastname: Nicholas
authors.forename: Jonathan
authors.initials: J
authors.lastname: Hodgkin
mesh_terms: D000192:Actinomycetales / Q000472:pathogenicity; D000818:Animals; D030801:Animals, Genetically Modified; D001424:Bacterial Infections; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000502:physiology*; D012734:Disorders of Sex Development / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D005801:Genes, Homeobox; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000502:physiology*; D008969:Molecular Sequence Data; D012007:Rectum / Q000196:embryology / Q000382:microbiology; D017384:Sequence Deletion; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D029742:Caenorhabditis elegans Proteins; C477318:Egl-5 protein, C elegans; D018398:Homeodomain Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins