Cloning and differential expression of two beta-pigment-dispersing hormone (beta-PDH) isoforms in the crab Cancer productus: evidence for authentic beta-PDH as a local neurotransmitter and beta-PDH II as a humoral factor.
Two beta-pigment-dispersing hormone (beta-PDH) isoforms have been identified in several decapod crustaceans, including the crab Cancer productus, but whether these peptides serve common or distinct physiological roles remains to be elucidated. Here we show that the distribution of beta-PDH-like immunoreactivity in the nervous system of C. productus is similar to that found in other brachyurans, suggesting roles as both a circulating hormone and a locally released transmitter for members of this peptide family. cDNAs encoding NSELINSILGLPKVMNDAamide (authentic beta-PDH; here termed Canpr-beta-PDH I) or NSELINSLLGLSRLMNEAamide [corrected](Canpr-beta-PDH II) were cloned. Double in situ hybridization revealed that these two beta-PDH isoforms are differentially distributed within the eyestalk. For example, in most neurons between the medulla interna (MI) and the medulla terminalis (MT), both isoforms appear present; however, in some neurons in this region, mRNA for only one or the other isoform was detected. Likewise, only prepro-beta-pdh I mRNA was detected in the somata of the lamina ganglionaris (LG) and in the brain. By direct tissue mass spectrometry, only Canpr-beta-PDH II was detected in the neurosecretory sinus gland (SG), whereas Canpr-beta-PDH I was found in all other parts of the eyestalk. Collectively, these data suggest distinct functions for each of the C. productus beta-PDHs; Canpr-beta-PDH II appears to be a neurohormone in the SG, whereas Canpr-beta-PDH I may function as a local transmitter/modulator. Our data support the hypothesis that duplication and subsequent mutation of a common neuropeptide gene may underlie the evolution of two differentially distributed transcripts that serve distinct physiological roles.
Hsu
Yun-Wei A
YW
Department of Biology, University of Washington, Seattle, Washington 98195-1800, USA.
Stemmler
Elizabeth A
EA
Messinger
Daniel I
DI
Dickinson
Patsy S
PS
Christie
Andrew E
AE
de la Iglesia
Horacio O
HO
D000818:Animals; D003386:Brachyura / Q000378:metabolism* / Q000648:ultrastructure; D003001:Cloning, Molecular / Q000379:methods*; D005583:Fourier Analysis; D015870:Gene Expression / Q000502:physiology*; D013058:Mass Spectrometry; D018613:Microscopy, Confocal; D009420:Nervous System / Q000378:metabolism; D010455:Peptides / Q000235:genetics* / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism
D010455:Peptides; D020033:Protein Isoforms; C027714:melanophore-dispersing hormone