CRUSTACEAN HYPERGLYCEMIC HORMONE OF THE RED DEEPSEA CRAB Chaceon quinquedens IDENTIFICATION AND ITS POTENTIAL ROLE AS A REPRODUCTIVE REGULATOR  

Shadaesha Green* and J. Sook Chung
Institute of Marine and Environmental Technology
University of Maryland Center for Environmental Science
701 E Pratt St., Baltimore MD, 21202
sgreen@umces.edu
 

The reproductive strategy of crustaceans is closely related to their life history and requires precise regulation of neuroendocrine and non-neuroendocrine related compounds. Our current knowledge that has been gleaned largely from the studies of warm water crustacean species suggests that hormones derived from the eyestalk ganglia mainly regulate various reproductive strategies in females. Specifically, members of crustacean hyperglycemic hormone (CHH) superfamily: crustacean CHH and molt-inhibiting hormone (MIH) stimulate and/or inhibit vitellogenesis, the process of yolk protein synthesis and accumulation in oocytes. Little has been known about the reproductive endocrinology of deepsea cold-water crustacean species including the red deepsea crab, Chaceon quinquedens.

The objective of this study is to identify putative reproductive/molting regulators of the female red deepsea crab. First, the presence of CHH has been established in the neurosecretory cells and the sinus gland of eyestalk ganglia using PAGE-Western blot analysis and immunohistochemistry. With a degenerate PCR and 5' and 3' RACE cloning strategy, the full-length cDNA sequence for CHH (ChqCHH) containing an unusually long 5', and a relatively short 3' untranslated region has been isolated. The putative amino acid sequence of ChqCHH is most closely related to the European green crab, Carcinus meanas CHH. Reverse-phase HPLC combined with a dot blot assay identifies the two isoforms of CHH (CHH1 and CHH2), with CHH2 as the major form. Additionally, using the same cloning strategy, a partial vitellogenin cDNA sequence of C. quinquedens encompassing the lipoprotein N-terminal domain (317 amino acids) was obtained and shares ~ 75% sequence identity with that of the snow crab, Chionoecetes opilio. The role of CHH in ovarian development is being currently investigated by establishing a relationship between expression levels of CHH and vitellogenin at varying ovarian stages.