FMRFamide-related peptides (FaRPs) are short neuropeptides that have been found throughout the animal kingdom. FaRPs have been shown to have many general functions, including cardioregulation, muscle control, pain modulation and learning. In C. elegans, at least 50% of the neurons are FMRFamide-like immunoreactive. To date, at least 20 genes,
flp-1 through
flp-20, encoding these peptides have been identified in C. elegans. To determine the cell specific expression of the flp genes in C. elegans, transgenic animals expressing a gfp (green fluorescent protein) reporter construct under the control of each flp promoter were generated. To date,
flp-3,
flp-5,
flp-8, and
flp-12 cell specific expression has been determined.
flp-3-expressing cells include three pairs of neurons (IL1D, OLL, URB), and one unpaired neuron (PQR).
flp-5-expressing cells include two pairs of neurons (ASE, RMG) and one unpaired neuron (I4).
flp-8-expressing cells include two pairs of neurons (ASE, URX) and one unpaired neuron (PVM).
flp-12-expressing cells include a set of four motorneurons (SMB) and two unpaired neurons (AVM, PVM).
flp-2,
flp10, and
flp-15 cell specific expression patterns are being determined. To determine the function of the flp genes in C. elegans, several flp deletion mutants, including
flp-3,
flp-7,
flp-8, and
flp-10, were isolated by screening Ron Plasterk's C. elegans EMS-mutagenized library. The size of the deletion in
flp-3 or
flp-8 deletion mutants is 2.6 kbp or 1.4 kbp, respectively, and deletes the entire coding region of both genes. Both
flp-3 and
flp-8 deletion mutants have not shown any phenotype so far, suggesting that these genes have overlapping functions with other flp genes. A
flp-10 deletion mutant is being backcrossed. In addition, transgenic worms containing a
flp-1,
flp-3, or
flp-8 cDNA under the control of the neural specific promoter were generated. These transgenic worms are being characterizing. To identify genes that may regulate expression of the flp genes, we are using transgenic animals expressing a gfp reporter construct under the control of
flp-1 or
flp-12 promoter in modifier screens. These worms are being mutagenized, and mutants showing altered expression of these markers are being isolated.