Project: Research project

Project Details


The morphogenesis of peripheral sense organs, known as rays, in the tail of
the C. elegans male will be studied by means of a combined genetic,
cellular, and molecular approach. Nine bilateral pairs of rays are present
at reproducible sites, forming a species-specific pattern in the tail. The
strategy to be taken to understand the generation of this pattern comprises
three steps: 1) Defining the determinative cellular events that govern
generation of the pattern, 2) Isolating and studying mutants, identifying
both the morphogenetic and regulatory genes and gene products that
participate in determinative cellular events, and 3) Learning how
morphogenetic and regulatory genes interact in a morphogenetic pathway.
The long term goal of this research is to understand how genes specify the
form of multicellular animals.

Three aspects of ray development are addressed:

1. Number of rays. The number of rays is determined by the specification
of a subset of cells that express the ray sublineage. The sublineage
generates two neurons and a support cell, which differentiate into a ray
during the last larval stage. In order to understand how initiation of the
ray sublineage is controlled, a genetic and molecular analysis of the lin-
32 gene, a key gene for entry into the neurogenic branch of the ray
sublineage, will be carried out. In order to learn how regulation of
expression of the ray sublineage differs in different cell lineages, a
similar analysis of the mab-19 gene, a gene required for expression of the
ray sublineage by a subset of related cells, will be carried out.
Preliminary analysis of eight mutations that block development of rays will
be completed, with particular emphasis on determining the cell lineage
defects, if any, in these mutants.

2. Generation of ray differences. Although they rise from a stereotyped
cell sublineage, the nine bilateral pairs of rays differ from each other
with respect to morphology, ultrastructure, neurotransmitter usage,
interactions with neighboring cells during development, and genetic
requirements. Laser ablation experiments will be carried out to define
cellular interactions that determine differences between the rays. Genetic
and molecular studies will be undertaken on five genes postulated to be
required for establishing the wild type pattern of ray differences.
3. Formation of a specific spatial arrangement of rays. A genetic and
molecular characterization will be carried out on the gene hypothesized to
participate during morphogenesis in interactions of ray cells required for
their correct positioning within the epidermis.
Effective start/end date7/1/926/30/93


  • National Institute of General Medical Sciences


  • Genetics
  • Radiation
  • Developmental Neuroscience
  • Molecular Biology
  • Developmental Biology

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