Purification, characterization and expression of two vitellogenins in the Indian freshwater murrel Channa punctatus

•The first report of existence of vga and vgb in a fish of Indian subcontinent.•Differential expression pattern of vga and vgb under estrogenic stimulation.•Different sensitivities of vga and vgb to estrogens.•A dual marker system (vga and vgb) to assess the presence of xenoestrogens in water.

The present study was undertaken to characterize different vitellogenins in Channa punctatus. Protein purification by gel chromatography followed by fast protein liquid chromatography (FPLC) revealed existence of two different Vg forms. Liquid chromatography tandem mass spectrophotometry (LC-MS/MS) suggested the existence of Vga and Vgb. Cloning of partial sequences of vga and vgb mRNA and phylogenetic analysis substantiated the existence of two vitellogenins. Real time PCR for vga and vgb genes from liver of estradiol-17β (E2) treated fish reveals difference in expression levels of transcripts of these two genes. vgb is expressed at lower dose of estradiol suggesting a higher sensitivity to estradiol. The present study thus proposes different regulatory control for the expression of these two genes and vgb as a superior biomarker than vga to assess exposure of C. punctatus to environmental estrogens.