| 作者： |
Wang, Bingchao; Zhu, Fangzheng; Shi, Zechao; Huang, Zhenyu; Sun, Ruhan; Wang, Qingchao; Gang, Ouyang; Ji, Wei |
| 论文摘要： |
The major histocompatibility complex (MHC) is an important component of the immune system of vertebrates, which plays a vital role in presenting extrinsic antigens. In this study, we cloned and characterized the mhc IIA and mhc IIB genes of yellow catfish Pelteobagrus fulvidraco. The open reading frames (ORFs) of mhc IIA and mhc IIB genes were 708 bp and 747bp in length, encoding 235 and 248 amino acids, respectively. The structure of mhc IIA and mhc IIB includes a signal peptide, an alpha 1/beta 1 domain, an alpha 2/beta 2 domain, a transmembrane region and a cytoplasmic region. Homologous identity analysis revealed that both mhc IIA and mhc IIB shared high protein sequence similarity with that of Chinese longsnout catfish Leiocassis longirostris. mhc IIA and mhc IIB showed similar expression patterns in different tissues, with the higher expression level in spleen, head kidney and gill and lower expression in liver, stomach, gall bladder and heart. The mRNA expression level of mhc IIA and mhc IIB in different embryonic development stages also showed the similar trends. The higher expression was detected from fertilized egg to 32 cell stage, low expression from multicellular period to 3 days post hatching (dph), and then the expression increased to a higher level from 4 dph to 14 dph. The mRNA expression levels of mhc IIA and mhc IIB were significantly up-regulated not only in the body kidney and spleen, but also in the midgut, hindgut, liver and gill after challenge of Flavobacterium columnare. The results suggest that Mhc II plays an important role in the anti-infection process of yellow catfish P. fulvidraco. |
