Protein Profiling and Precursor-product Relationship between Vitellogenin and Lipovitellin in the African catfish, Clarias gariepinus

Abstract

Nutrients are deposited in the eggs as yolk to provide energy and to build embryonic structures. Lipovitellin, the major egg-yolk protein was purified from the oocytes of Clarias gariepinus. The amino acid sequences of lipovitellin (Lv) peptides obtained by Mass spectrometry were mapped on its precursor protein, Vitellogenin (Vg). Advanced proteomic tools, PAGE {one dimensional (1-D) andtwo dimensional (2-D)} and mass spectrometry were employed to characterise Vg. Similarity in sequences of peptidesre-established the precursor-product relationship between Vg and Lv. Partial mRNA transcript of vg gene was translated into amino acid sequence that corresponded to conserved domains of Vitellogenin in NCBI database. Phylogenetic analysis of the nucleotide sequence of Africancat fish vg gene revealed a close similaritywith the fishes of the order Siluriformes.