Research
| Title： | MHC II system of mandarin fish (Siniperca chuatsi): Gene identification, expression analysis and transcriptional regulation |
|---|---|
| First author： | Hou, Jing; Qi, Lu; Cao, Ran; Liu, Lan Hao; Chen, Shan Nan; Nie, Pin |
| Journal： | AQUACULTURE |
| Years： | 2025 |
| DOI： | 10.1016/j.aquaculture.2025.743074 |
| Abstract： | This study aimed to investigate the composition, structural feature, expression pattern, and transcriptional regulation of major histocompatibility complex (MHC) II genes in mandarin fish (Siniperca chuatsi). Through bioinformatics and molecular biology approaches, seven MHC II genes were identified and classified into DA, DB, and DE lineages, among which MHC II DBA seems to be a possible pseudogene. Thus, six functional MHC II genes were identified, including DAA1, DAB1, DAA2, DAB2, DEA, and DEB. The chromosomal location and genomic structure of these genes were further investigated, showing that they are unlinked to MHC I genes and are distributed across different chromosomes. Sequence analysis demonstrated the peptide-binding regions of DA lineage genes displayed high polymorphism. Constitutive expression analysis showed that MHC II genes were expressed in all examined tissues / organs, with the DA lineage genes showing higher expression level than the DE lineage genes. The high polymorphism and high expression level of DA lineage genes are characteristic of classical MHC II genes. Moreover, in response to stimulation, the expression of MHC II genes was induced by immune stimulants such as PolyI:C, LPS, and PGN, as well as by recombinant IFN-c, IFN-h, and IFN-gamma. Furthermore, potential regulatory elements, including ISRE, X1, X2, and Y box, were identified in promoter region of MHC II genes. Notably, ISRE motif is essential for the activation of MHC II promoters by IRF1, while X1 and X2 motifs appear to play a critical role in MHC II promoter activation by CIITA. These findings provide valuable insights into the evolutionary pattern and immune regulatory networks of MHC II genes in fish. |
