Characterization of an additional molt inhibiting hormone-like neuropeptide from the shrimp Metapenaeus ensis.
We have identified a second form of the type-II neuropeptide encoding a molt inhibiting hormone-like (MeeMIH-B) neuropeptide. MeeMIH-B showed only a 70% amino acid identity to the MIH-A (formerly MIH) isolated from the same species, suggesting a possible different function of the deduced neuropeptide. Like other neuropeptide members of the CHH family, the MIH-B gene consists of three exons separated by two introns. The levels of MIH-B mRNA transcript in the eyestalk decrease in the initial phase of gonad maturation and increase towards the end of maturation. The drop in MIH-B level suggests an inhibitory role for this neuropeptide in the initiation of vitellogenesis. MIH-B transcripts can also be detected in the brain, thoracic ganglion and ventral nerve cord. Together with the CHH-B peptide that we have previously described, this is the second peptide of the CHH family that can also be identified in the ventral nerve cord and in the XOSG complex. A recombinant MIH-B was produced and a polyclonal antibody against rMIH-B was subsequently generated. Specific anti-rMIH-B antiserum recognized the presence of MIH-B in the sinus gland, X-organs, as well as a giant neuron of the ventral nerve cord. Injection of rMIH-B delayed the molting cycle of the maturing female. Taken together, the results of this study suggest that a drop in MIH-B level may be required for the delay in the molting of the maturing females.
Gu
P-L
PL
Department of Zoology, The University of Hong Kong, Pokfulam Road, PR China.
Tobe
S S
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Chow
B K C
BK
Chu
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KH
He
J-G
JG
Chan
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SM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003445:Crustacea / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D007150:Immunohistochemistry; D007447:Invertebrate Hormones / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D007447:Invertebrate Hormones; D009479:Neuropeptides; D011994:Recombinant Proteins; C088772:molt-inhibiting hormone-like neuropeptide