Identification of immune responsible fibrinogen beta chain in the liver of large yellow croaker using a modified annealing control primer system.

In this article, we used a modified ACP system (mACP) developed in our laboratory to analyze differentially expressed genes in the liver of large yellow croaker, Pseudosciaena crocea (Richardson). By using 20 pairs of mACPs, 7 differentially expressed genes were obtained. One of the genes we identified encodes for a fibrinogen beta chain (FGB). The full-length cDNA of FGB was 1645 bp, including 5 bp of 5' untranslated region (5'-UTR), 1479 bp of open reading frame (ORF), and 161 bp of 3'-UTR. The ORF was capable of encoding 492 amino acids with an estimated molecular mass of 55.6 kDa, giving it a predicted pI of 5.94. The deduced amino acid sequence included an FGB profile (V(238)-Y(488)) and an FGB family signature (WWYNRCHSANPNG). Multiple sequence alignments indicated that the large yellow croaker FGB showed homology with FGB sequences of other species (45-77% identity). Real time PCR analysis demonstrated that the expression of FGB in the liver of large yellow croaker injected with Vibrio parahaemolyticus was significantly (P < 0.05) lower than that of the control group at 8 d, which confirmed the expression patterns of the results of mACP differential display.