雉科鸟类抗病毒基因BF和Mx分子进化研究

发布时间：2018-04-17 12:33

本文选题：雉科鸟类 + BF　；参考：《东北林业大学》2016年硕士论文

【摘要】：目前鸟类各种传染性疾病对种群数量构成严重威胁,因此鸟类抗病性研究已成为热点。BF基因和Mx基因均是自然选择作用下产生的抗病性基因,并且这两种基因的多态性在鸟类抵抗感染和自身免疫疾病方面起着至关重要的作用,同时也是禽类抗病育种的有效候选基因。本研究以黄腹角雉等10种雉科鸟类为研究对象,通过直接测序或平端克隆的方法获得黄腹角雉3个个体的BF基因外显子2-8序列和5种雉科鸟类的BF基因外显子2、3序列以及10种雉科鸟类Mx基因外显子13和外显子14序列。并探讨这两种基因的多态性及进化,为进一步研究鸟类BF和Mx基因的抗病性奠定理论基础,结果如下：1.获得黄腹角雉3个个体的BF基因部分序列,包括7个外显子(外显子2-8)和6个内含子(内含子2-7),确定了9个单倍型,序列长1803～1828bp,编码区长1010bp,共编码335个氨基酸。9个单倍型中,核苷酸变异位点最丰富的区域位于al(exon2编码)和a2 (exon3编码)结构域构成的抗原结合区。2.从雉科5种鸟类的25个个体的125条有效的BF exon2、3完整编码区克隆序列中确定了20个单倍型,序列长544bp,共编码181个氨基酸,核苷酸变异位点192个,其中简约信息位点126个。3.获得雉科10种鸟类的Mx基因外显子13和外显子14序列,其中外显子13的40条序列中确定了18个单倍型,外显子14的58条序列中确定了13个单倍型,结果显示外显子14更加保守。4.BF基因的α1结构域抗原结合区(PBR)受正选择作用,而非抗原结合区(non-PBR)受净化选择作用；α2结构域,无论是抗原结合区(PBR)还是非抗原结合区(non-PBR)皆受到净化选择作用,但抗原结合区的非同义替换率均大于非抗原结合区。Mx基因的GED区以及位于GED区控制Mx蛋白抗病毒活性的S631N突变位点则均受净化选择作用。5.BF基因和Mx基因中皆存在属内与属间共享单倍型,并且BF基因所构建的进化树显示出此基因的跨物种进化现象。6.本实验获得的雉科10种鸟类Mx基因第631位氨基酸均为丝氨酸(Ser),所以推测本研究的这十种野生雉科鸟类群体皆属于易感群体。
[Abstract]:At present, a variety of infectious diseases in birds pose a serious threat to the population, so the study of bird disease resistance has become a hot spot. BF gene and Mx gene are the resistance genes produced by natural selection.The polymorphism of these two genes plays an important role in bird resistance to infection and autoimmune diseases, and is also an effective candidate gene for avian disease resistance breeding.In this study, 10 species of pheasants, such as the Yellow Pheasant, were selected as the research objects.The exon 2-8 sequence of BF gene in three individuals of the pheasant and the sequence of exon 2C3 of BF gene in 5 species of pheasants, and the sequence of exon 13 and exon 14 of Mx gene in 10 species of pheasants were obtained by direct sequencing or flat-end cloning.The polymorphism and evolution of the two genes were discussed, which laid a theoretical foundation for further study on the resistance of BF and Mx genes in birds. The results are as follows: 1.The BF gene partial sequences of three individuals of the pheasant were obtained, including 7 exons (exon 2-8) and 6 introns (intron 2-7). Nine haplotypes were identified, the length of the sequence was 1803 ~ 1828 BP, and the coding region was 1010 BP, encoding a total of 335 amino acids.The most abundant regions of nucleotide variation are located in the antigen-binding region of al(exon2 coding) and a2 + exon3) domain.Twenty haplotypes, encoding 181 amino acids and 192 nucleotide mutation sites, were identified from 125 effective BF exon 2N 3 complete coding regions from 25 individuals of 5 species of the pheasant family, with a total length of 544bp. among them, the reduced information sites were 126. 3.Exon 13 and exon 14 sequences of Mx gene were obtained from 10 species of pheasant family. Among them, 18 haplotypes were identified in 40 exon 13 sequences and 13 haplotypes were identified in 58 exon 14 sequences.The results showed that exon 14 was more conserved. 4. The 伪 1 domain antigen binding region (PBR) of BF gene was positively selected, but the non-antigen binding region (non-PBR) was purified and the 伪 2 domain was purified.Both antigen-binding region (PBR) and non-antigen binding region (non-PBR) were purified and selected.However, the non-synonymous substitution rate of antigen binding region was higher than that of GED region of non-antigen binding region. Mx gene and S631N mutation site located in GED region which controlled the antiviral activity of Mx protein. 5. BF gene and Mx gene were all purified and selected.Shared haplotypes within and between genera,Furthermore, the evolutionary tree constructed by BF gene showed the cross species evolution phenomenon of BF gene.The amino acids at position 631 of Mx gene of 10 species of pheasants in this study were all serine serine, so we speculate that all the ten species of wild birds in this study belong to susceptible populations.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：Q953

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