Vol. 38 No. 1, 1999

Isolation and Characterization of a Novel Peptide Gene in the Lobster Jasus edwardsii

Jenny G.I. Khoo and Frank Y.T. Sin*

Department of Zoology, University of Canterbury, Christchurch, Private Bag 4800, New Zealand

Jenny G.I. Khoo and Frank Y.T. Sin (1999) Previous studies have demonstrated an immunological and functional relationship between vasopressins and the moult-inhibiting hormone (MIH) of crustaceans. Using primers derived from the rat vasopressin gene, 2 fragments were amplified from the genomic DNA of the lobster Jasus edwardsii. This paper describes the characterization of the 960-bp sequence. Northern blot analysis showed that the 960 bp sequence was expressed in the epithelia, eyestalk, heart, hepatopancreas, and muscle, but expression was most prominent in the eyestalk. In situ hybridization using the 960-bp sequence as a probe detected RNAs in the neurosecretory regions of the eyestalk. The expression of these genes appeared to be higher in the intermoult than the ecdysial eyestalk. Sequence analysis of the 960-bp PCR product revealed an intron/exon splice junction, a protein coding region with a stretch of repetitive sequences which is translated into a metallothionein-Iike protein. Furthermore, the 960- bp sequence also shared over 40% sequence homology to rat vasopressin, and MIH and CHH of some crustaceans. We called this sequence the Novel Peptide Sequence (NPS).

Key words: Lobster, Vasopressin-like gene, Moult-inhibiting hormone, Eyestalk, Metallothionein-like protein.

*Correspondence: Fax: 64-03-3642024. E-mail: f.sin@csc.canterbury.ac.nz