Worm Breeder's Gazette 9(3): 110

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

FMRFamide-Like Immunoreactivity in C. elegans

C. Li and M. Chalfie

The neuropeptide FMRFamide (Phe-Met-Arg-Phe-amide) and peptides 
homologous to FMRFamide have been found throughout the animal kingdom 
where they have been implicated as neurotransmitters, neurohormones, 
and neuromodulators Using polyclonal antibodies raised against 
synthetic FMRFamide (donated by R Calabrese and T. O'Donohue) and a 
whole mount staining procedure modified from S McIntire, C. Desai, and 
R H Horvitz, we mapped the distribution of FMRFamide-like 
immunoreactivity in N2 adult hermaphrodites There are at least nine 
immunoreactive cells (some paired, some unpaired) around the nerve 
ring, six cells along the ventral cord, one pair of lateral cells near 
the position of the vulva, one cell in the dorsal-rectal ganglion, and 
one cell in the pre-anal ganglion In addition, the nerve ring is 
intensely labelled, there are numerous immunoreactive processes 
running throughout the length of the ventral cord (all but one of 
these processes run on the same side of the hypodermal ridge as the 
immunoreactive cells in the cord), one process, which runs the entire 
length of the animal, in the dorsal cord and each lateral cord, and a 
complex arborization of immunoreactive processes that may innervate 
the vulva muscles Preincubation of the antiserum with synthetic 
FMRFamide eliminates staining in the 
Tentative identification of many of the FMRFamide-like 
immunoreactive cells have been deduced from analysis of mutants and 
from the morphology and position of the cells. For example, the number 
and position of the immunoreactive cell bodies in the ventral cord 
corresponds to the VC motoneurons Furthermore, staining of lin-39 
mutants, in which many of the VC motoneurons die, reveals fewer cell 
bodies and processes in the ventral cord, supporting the 
identification of the ventral cells as the VC motoneurons Other 
identified cells include the RID motoneuron, either the RIF or RIG 
interneurons, the DVB interneuron/motoneuron, and the PVT cell We have 
recently discovered that staining of neurons and processes in the 
cords can be optimized by using animal fragments, which are derived by 
gentle homogenization of formaldehyde-fixed animals This procedure has 
allowed more consistent visualization of immunoreactivity in two cell 
types, the ALA cell and the CAN 
Acetone extracts of whole animals contain 120 nmoles of FMRFamide-
like peptide per gram wet weight, as measured by radioimmunoassay (RIA)
The antibody displays a similar recognition to the C. 
s) and to synthetic FMRFamide Based on 
antibody specificities (Marder et al , 1986) these data suggest that 
the antigen(s) contains at least a terminal -ArgPhe-amide We intend to 
purify and sequence the FMRFamide-like peptide(s) from C elegans.We 
are continuing to screen unc mutants to identify animals that have 
FMRFamide-related defects or that are FMRFamide-deficient. In addition,
we are examining target cell (vulval muscles) influences on the 
induction or stabilization of (VC and PVT) processes in Vulvaless, 
Multi vulva, and Egghead mutants We will confirm that the CAN cells 
contain FMRFamide by examining vab-8 mutants, which have misplaced CAN 
cells. The CAN cells are believed to be secretory cells and have been 
shown to be critical for 
survival of young animals and for the proper development of the 
posterior half of the animal (J Sulston and J. Hodgkin, WBG 5(1), 1980)
. As neuropeptides function as neurohormones in many instances, the 
FMRFamidelike peptide may be one of the neurohormones secreted by the 
CAN cells during the development of the animal; animals that lack 
FMRFamide may have a phenotype similar to animals that have CAN cell-
related defects Lastly, we have obtained an APlysia cDNA clone 
encoding FMRFamide from R Scheller Using this Aplysia clone to probe a 
C. lambda library (a gift from S Emmons), we 
have isolated two positive clones, which will be subcloned and