Identification of five genes from Wnt/β-catenin pathway inyellow catfish (Pelteobagrus fulvidraco) and their mRNA expression inthe ovary to waterborne copper exposure

Five complete cDNA sequences related to Wnt/β-catenin signal pathway, designated wnt2, wnt2bb, wnt3a, wnt8a and ctnnb1, were amplified by RT-PCR and RACE approaches from yellow catfish (Pelteobagrus fulvidraco). The validated cDNAs encoding wnt2, wnt2bb, wnt3a, wnt8a and ctnnb1 were 1 743, 2 133, 1 379, 1 508 and 2 636 bp in length, encoding peptides of 351, 372, 291, 387 and 791 amino acid residues, respectively. The amino acid alignment and phylogenetic analysis revealed that these sequences were relatively conserved among vertebrates, and Wnt/β-catenin genes of P. fulvidraco were more closely related to those of Astyanax mexicanus. All Wnt/β-catenin mRNAs were expressed in nine tested tissues (brain, spleen, kidney, gill, heart, muscle, mesenteric fat, liver and ovary), but at variable levels. Effect of waterborne Cu exposure on ovarian mRNA levels of the five genes of P. fulvidraco were determined. On day 28, wnt3a mRNA levels in the ovary significantly decreased with increasing waterborne Cu concentration, but wnt8a showed the opposite trend. On day 56, mRNA levels of these five genes from the ovary of P. fulvidraco showed no significant differences among the three groups. The present study may be helpful to understand the physiological functions of Wnt/β-catenin pathway in fish.