Morphological Diversity of C. elegans Sensory Cilia Instructed by the Differential Expression of an Immunoglobulin Domain Protein

Curr Biol. 2017 Jun 19;27(12):1782-1790.e5. doi: 10.1016/j.cub.2017.05.006. Epub 2017 Jun 1.

Abstract

Cilia on dendritic endings of sensory neurons organize distinct types of sensory machinery [1]. Ciliated endings display neuron-type-specific patterns of membrane elaborations [1-3], but it is not well understood how such neuron-type-specific morphologies are generated and whether they are coupled to the specification of other identity aspects of a terminally differentiated sensory neuron. In the course of a genome-wide analysis of members of a small family of immunoglobulin domain proteins, we found that OIG-8, a previously uncharacterized transmembrane protein with a single immunoglobulin (Ig) domain, instructs the distinct, neuron-type-specific elaboration of ciliated endings of different olfactory neuron types in the nematode C. elegans. OIG-8 protein localizes to ciliated endings of these sensory neurons, and is transcribed at different levels in distinct olfactory neuron types. oig-8 expression levels correlate with the extent of sensory cilia growth and branching patterns. Loss of oig-8 leads to a reduction in the branching patterns of cilia, whereas raising the levels of oig-8 results in an increase in elaborations. Levels of OIG-8 expression are controlled by the specific combination of a terminal selector type of transcription factors that also specify other identity features of distinct olfactory neuron types.

Keywords: C. elegans; cilia; neuronal diversity.

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / metabolism
  • Cilia / genetics*
  • Cilia / metabolism
  • Immunoglobulin Domains / genetics*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • OIG-1 protein, C elegans
  • OIG-8 protein, C elegans