The helminth Schistosoma mansoni expresses a peptide similar to human beta-endorphin and possesses a proopiomelanocortin-related gene.
Opioid peptides, a group of transmitter substances with a high degree of phylogenic conservation, have many different functions, including a role in modulation of cells of the immune system. We have postulated the existence of such peptides in the parasite Schistosoma mansoni in view of their possible role in host-parasite interactions. In this report we show that beta-endorphin, which is a member of the opiate family and is derived from the proopiomelanocortin (POMC) precursor, is present in S. mansoni. Southern blots of cercarial genomic DNA, hybridized with two oligonucleotide probes complementary to highly conserved POMC sequences, showed a POMC-related gene in this trematode. Northern blot analysis of adult worm RNA indicated that this gene was actively transcribed. Significant amounts of beta-endorphin, adrenocorticotropin (ACTH), and alpha-melanocyte stimulating hormone (alpha-MSH) were detected in all developmental stages of the parasite by radioimmunoassays with the use of antisera to human peptides. By means of reverse-phase high-performance liquid chromatography (HPLC), we found that the parasite beta-endorphin-like material and the human opiate have a high degree of homology. These results appear to constitute the first demonstration of a POMC-related gene transcribed in an invertebrate.
Duvaux-Miret
O
O
Centre d'Immunologie et de Biologie Parasitaire, Unité mixte INSERM U 167, CNRS 624, Institut Pasteur, Lille, France.
Dissous
C
C
Gautron
J P
JP
Pattou
E
E
Kordon
C
C
Capron
A
A
D000324:Adrenocorticotropic Hormone / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D015342:DNA Probes; D004723:Endorphins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007814:Larva; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D011333:Pro-Opiomelanocortin / Q000235:genetics*; D012550:Schistosoma mansoni / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D000521:alpha-MSH / Q000235:genetics; D001615:beta-Endorphin / Q000235:genetics*
D015342:DNA Probes; D004723:Endorphins; D000521:alpha-MSH; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D004247:DNA