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Goldsinny wrasse ( Ctenolabrus rupestris ) is an extreme vtgAa ‐type pelagophil teleost
Author(s) -
Kolarevic Jelena,
Nerland Audun,
Nilsen Frank,
Finn Roderick Nigel
Publication year - 2008
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20845
Subject(s) - biology , vitellogenin , oocyte , vitellogenins , yolk , amino acid , cleavage (geology) , proteolysis , biochemistry , microbiology and biotechnology , gene , vitellogenesis , fishery , embryo , paleontology , fracture (geology) , enzyme
During oocyte maturation in the goldsinny wrasse ( Ctenolabrus rupestris ) extensive proteolysis of yolk proteins generates a large pool of free amino acids that drive hydration of the pelagic egg. By cloning hepatic vitellogenins ( vtg ) and using mass spectrometry, N‐terminal microsequencing, and Western‐immunoblotting to identify the yolk proteins (Yp), we show that multiple forms of vitellogenin mRNAs ( vtgAa , vtgAb , and vtgC ) are expressed in the liver, but only a single major class of the Yps derived from vtgAa predominates in the oocytes. Some Yps derived from vtgAb and vtgC appear also to be incorporated in the oocytes and eggs, but only at background levels. During oocyte hydration the vtgAa ‐derived lipovitellin heavy chain (LvH‐Aa) and its cleavage variants are completely degraded leaving only a processed lipovitellin light chain (LvL‐Aa) fragment as the major yolk protein for embryonic development. The maturational cleavage site of the LvL‐Aa is identified as two amino acids downstream from the conserved Tyr 1168 of VtgAa in Atlantic halibut. In addition, although a β′‐component (∼18 kDa) is present in the oocytes, it is not fully degraded during the hydration process. Mol. Reprod. Dev. 75: 1011–1020, 2007. © 2007 Wiley‐Liss, Inc.