Loer Lab

Serotonergic neurons in male C. elegans

Serotonin-containing neurons of C. elegans male revealed by serotonin antisera and rhodamine-conjugated secondary antibody. [Composite of scans from two slides taken by C. Ramirez; retouched and enhanced with Adobe Photoshop.] Click here for a figure identifying these cells.

[update]24 October 2011
A fundamental problem in developmental neurobiology is to understand how nerve cells (neurons) choose their identities. One critical decision a neuron makes during development is its choice of neurotransmitter -- that is, the chemical substance it uses to relay information to another neuron. To use a particular neurotransmitter, a neuron must express a unique set of proteins by activating specific genes. We are studying the control of this process in a simple organism, the free-living nematode, Caenorhabditis elegans, which has only about 1000 cells, a third of which are neurons. C. elegans is one of the premier model organisms in biology today. This free-living soil nematode (roundworm) was the first multicellular organism for which scientists obtained a complete genomic DNA sequence. This tiny worm shares many common developmental mechanisms with higher animals.

We are interested in how genes required by neurons that use the neurotransmitter serotonin are regulated, and the behaviors controlled by serotonergic neurons. We are also interested in the evolution of behavior and neuronal patterning in the nervous system. We have begun to examine the patterning of serotonergic neurons in a variety of related nematodes, and to examine the behaviors regulated by serotonin in those species, such as the experience-dependent regulation of locomotion, egg-laying and male mating.

The enzymes catalyzing the first steps in serotonin and dopamine synthesis (Tryptophan hydroxylase and Tyrosine hydroxylase, respectively) both require a cofactor called biopterin. They share this feature with another aromatic amino acid hydroxylase (AAH) called phenylalanine hydroxylase (PAH) which converts the amino acid phenylalanine to tyrosine. In C. elegans, PAH is expressed in skin cells and seems to be necessary for proper cuticle construction. Biopterin is synthesized in the cells that need it; therefore serotonergic and dopaminergic neurons and skin cells also express biopterin synthesis (and related) genes. Because of these connections, we are also studying the function of PAH and biopterin in both the skin and neurons.

More on Loer Lab Research:
Papers & Abstracts
Serotonin-containing neurons of C. elegans
Protocols, etc.
Dopamine-containing neurons of C. elegans

I am always looking for good students to work in the lab. If you are interested, please contact me.

Current Members of the Loer Lab

Former Members of the Loer Lab

Lab Snapshots

We would also like to acknowledge the generous support of the Fletcher Jones Foundation, which endowed the Fletcher Jones Chair in Biology at USD.