Isolation of AF2 (KHEYLRFamide) from Caenorhabditis elegans: evidence for the presence of more than one FMRFamide-related peptide-encoding gene.
Numerous FMRFamide-related peptides (FaRPs) have been isolated and sequenced from extracts of free-living and parasitic nematodes. The most abundant FaRP identified in ethanolic/methanolic extracts of the parasitic forms, Ascaris suum and Haemonchus contortus and from the free-living nematode, Panagrellus redivivus, was KHEYLRFamide (AF2). Analysis of the nucleotide sequences of cloned FaRP-precursor genes from C. elegans and, more recently, Caenorhabditis vulgaris identified a series of related FaRPs which did not include AF2. An acid-ethanol extract of Caenorhabditis elegans was screened radioimmunometrically for the presence of FaRPs using a C-terminally directed FaRP antiserum. Approximately 300 pmols of the most abundant immunoreactive peptide was purified to homogeneity and 30 pmols was subjected to Edman degradation analysis and gas-phase sequencing. The unequivocal primary structure of the heptapeptide, Lys-His-Glu-Tyr-Leu-Arg-Phe-NH2 (AF2) was determined following a single gas-phase sequencing run. The molecular mass of the peptide was determined using a time-of-flight mass spectrometer and was found to be 920 (MH+)+, which was consistent with the theoretical mass of C-terminally amidated AF2. These results indicate that C. elegans possesses more than one FaRP gene.
Marks
N J
NJ
Comparative Neuroendocrinology Research Group, Queen's University of Belfast, Northern Ireland.
Shaw
C
C
Maule
A G
AG
Davis
J P
JP
Halton
D W
DW
Verhaert
P
P
Geary
T G
TG
Thompson
D P
DP
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D019835:FMRFamide; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000302:isolation & purification*
D009479:Neuropeptides; C073964:AF2 neuropeptide; D019835:FMRFamide