The Relationship Between the Alternative exon 7 Splice Variant of the BF Gene and MHC‐Related Marek's Disease Resistance in Chickens

Abstract

The study was to analyse the relationship between the alternative exon 7 splice variant of the BF gene and MHC-related Marek's disease (MD) resistance in chickens. The experiment first determined whether or not the cocks of Xiayan chickens have alternative splicing-out of the exon 7 of the BF gene from peripheral blood leucocytes (PBLs). Then, selected two groups: Group K included the offspring of the selected cocks which have no alternative splicingout of the exon 7 of the BF gene; Group Y included the offspring of the selected cocks which have alternative splicing-out of the exon 7 of the BF gene. All hens used in the cross-breeding were non-selected. The experimental chickens were challenged with a very virulent strain of Marek's disease virus (MDV) at 4 days old and were raised for 12 weeks. At this time, all the surviving chickens were killed and necropsy was also performed during the experiment whenever chickens died from the infection. Tumour incidence and mortality were calculated using SPSS, and the tissues were collected to detect MDV by PCR. The results showed that the mortalities of Group K and Y were 52.75% and 70.65%, respectively; and that the tumour incidences of non-alternative splicing-out of the exon 7 of the BF for Groups K and Y were 15.38% and 38.89%, respectively; the tumour incidences for the alternative splicing-out of the exon 7 were 46.15% and 56.76%, respectively. The results demonstrated the tumour incidence was highly related with the alternative exon 7 splice variant of the BF gene (P < 0.05).

Exploration of Alternative Splicing (AS) Events in MDV-Infected Chicken Spleens

“…Many viral genes in MDV genome have been identified that may involve in MD development, such as, meq [ 47 ], viral telomerase RNA (vTR) [ 48 ], viral interleukin-8 (vIL-8) [ 49 ], phosphoprotein 38 (pp38) [ 50 , 51 ], and MDV miRNAs [ 52 ]. For host genome, some genes involved in MD pathogenies were identified, including MHC [ 27 , 53 ], gga-miR-155 [ 54 ], gga-miR-26a and NEK6 [ 55 ], IGFBP7 and TNFRSF8 [ 39 ]. Several studies also illustrated the mechanism of susceptive or resistance from the epigenomic level [ 56 , 57 , 58 ].…”

“…Several studies also illustrated the mechanism of susceptive or resistance from the epigenomic level [ 56 , 57 , 58 ]. Alternative splicing transcripts were also detected in MD pathogenies [ 27 , 29 ].…”

“…It reported that meq bound to host genomic chromatin may contribute to MDV-mediated T-cell transformation and lymphomagenesis [ 26 ]. Jin et al [ 27 ] analyzed the relationship between the alternative exon 7 splice variant of the BF gene and MD resistance. They found that tumor incidence and mortality were highly related to the alternative exon 7 of the BF gene.…”

The Relationship Between the Three‐Dimensional (3D) Structures of BF Molecules and MHC‐Related Marek's Disease Resistance in Chickens

“…The larger central cavity in groove confers substantial conformational flexibility to the crucial residue Arg9, which allows remodelling of key peptide-binding sites and allows peptides with conspicuously different sequences to be bound. This might explain that the exon 7-deprived variant of the BF was detected in MD-susceptible haplotypes, but not in MD-resistant haplotypes [1][2][3].…”

Comparison of Full‐length Amino Acid Sequences of Chickens BF1 and BF2

“…Sample of cDNA extracted from peripheral blood leucocytes (PBL) of Xiayan chickens [2] was used in the experiment. The detailed steps of total RNA isolation and reverse transcription (RT) are described in the previous article [3].…”