The HLH-6 transcription factor regulates C. elegans pharyngeal gland development and function

PLoS Genet. 2008 Oct;4(10):e1000222. doi: 10.1371/journal.pgen.1000222. Epub 2008 Oct 17.


The Caenorhabditis elegans pharynx (or foregut) functions as a pump that draws in food (bacteria) from the environment. While the "organ identity factor" PHA-4 is critical for formation of the C. elegans pharynx as a whole, little is known about the specification of distinct cell types within the pharynx. Here, we use a combination of bioinformatics, molecular biology, and genetics to identify a helix-loop-helix transcription factor (HLH-6) as a critical regulator of pharyngeal gland development. HLH-6 is required for expression of a number of gland-specific genes, acting through a discrete cis-regulatory element named PGM1 (Pharyngeal Gland Motif 1). hlh-6 mutants exhibit a frequent loss of a subset of glands, while the remaining glands have impaired activity, indicating a role for hlh-6 in both gland development and function. Interestingly, hlh-6 mutants are also feeding defective, ascribing a biological function for the glands. Pharyngeal pumping in hlh-6 mutants is normal, but hlh-6 mutants lack expression of a class of mucin-related proteins that are normally secreted by pharyngeal glands and line the pharyngeal cuticle. An interesting possibility is that one function of pharyngeal glands is to secrete a pharyngeal lining that ensures efficient transport of food along the pharyngeal lumen.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Base Sequence
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / physiology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development*
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / physiology*
  • DNA, Helminth / genetics
  • Gene Expression Regulation, Developmental
  • Gene Regulatory Networks
  • Genes, Helminth
  • Helminth Proteins / metabolism
  • Mucins / metabolism
  • Mutation
  • Pharynx / growth & development*
  • Pharynx / physiology*
  • Phenotype
  • Sequence Homology, Nucleic Acid


  • Basic Helix-Loop-Helix Transcription Factors
  • Caenorhabditis elegans Proteins
  • DNA, Helminth
  • HLH-6 protein, C elegans
  • Helminth Proteins
  • Mucins