Molecular cloning of cDNAs encoding two pigment-dispersing hormones and two corresponding genes from the kuruma prawn (Penaeus japonicus).

Pigment-dispersing hormone (PDH) controls pigment dispersion in chromatophores. In this study cDNAs encoding 2 PDH precursors of the kuruma prawn (Penaeus japonicus) (Pej-PDH-I and Pej-PDH-II) were cloned. Both precursors consisted of a signal peptide, a PDH-precursor-related peptide (PPRP), and PDH. The PPRPs were homologous to those in other crustacean species, but not to those of pigment-dispersing factors (PDFs) in insects, which were members of the PDH/PDF family. Two corresponding genes were also cloned. Sequence analyses revealed that the Pej-PDH-I gene had 3 exons separated by 2 introns, while the Pej-PDH-II gene had 2 exons separated by 1 intron. The exon/intron organizations in the PDH genes were different from that of the Drosophila melanogaster PDF gene, which is intronless. Analyses by reverse transcription polymerase chain reaction demonstrated that both transcripts existed only in the eyestalk, but not in the brain, thoracic ganglia, abdominal ganglia, hindgut, or hepatopancreas.