Evidence for Conservation of the Vasopressin/Oxytocin Superfamily in Annelida*
- From the ‡Suntory Institute for Bioorganic Research, Wakayamadai 1-1-1, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan and the ¶Department of Biological Science, Faculty of Science, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima-city, Hiroshima 739-8526, Japan
Abstract
Annetocin is a structurally and functionally oxytocin-related peptide isolated from the earthworm Eisenia foetida. We present the characterization of the annetocin cDNA. Sequence analyses of the deduced precursor polypeptide revealed that the annetocin precursor is composed of three segments: a signal peptide, an annetocin sequence flanked by a Gly C-terminal amidation signal and a Lys-Arg dibasic processing site, and a neurophysin domain, similar to other oxytocin family precursors. The proannetocin showed 37.4–45.8% amino acid homology to other prohormones. In the neurophysin domain, 14 cysteines and amino acid residues essential for association of a neurophysin with a vasopressin/oxytocin superfamily peptide were conserved, suggesting that the Eisenia neurophysin can bind to annetocin. Furthermore, in situ hybridization experiments demonstrated that the annetocin gene is expressed exclusively in neurons of the central nervous system predicted to be involved in regulation of reproductive behavior. These findings confirm that annetocin is a member of the vasopressin/oxytocin superfamily. This is the first identification of the cDNA encoding the precursor of an invertebrate oxytocin-related peptide and also the first report of the identification of an annelid vasopressin/oxytocin-related precursor.
Footnotes
-
↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence reported in this paper has been submitted to the DDBJ/GenBankTM/EBI Data Bank with accession number AB014478.
-
↵§ To whom correspondence should be addressed. Tel.: 81-75-962-3743; Fax: 81-75-962-2115; E-mail: Hiroyuki_Minakata{at}suntory.co.jp.
-
↵2 Y. Fujino, T. Nagahama, T. Oumi, K. Ukena, F. Morishita, Y. Furukawa, O. Matsushima, M., Ando, H. Takahama, H. Satake, H. Minakata, and K. Nomoto, manuscript in preparation.
-
↵3 H. Satake, K. Kami, and H. Minakata, unpublished results.
- Abbreviations:
- VP
-
vasopressin
- OT
-
oxytocin
- RACE
-
rapid amplification of cDNA ends
- PCR
-
polymerase chain reaction
- DIG
-
digoxigenin
- PBS
-
phosphate-buffered saline
-
- Received October 26, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
