The follicle promotes the evolution of variants of avian leukosis virus subgroup J in vertical transmission

• Published in: Biochemical and biophysical research communications Vol. 521; no. 4; pp. 1089 - 1094
• Main Authors: Gao, Xintao, Li, Qiuchen, Fang, Lichun, Song, Haozhi, Cui, Zhizhong, Meng, Fanfeng, Zhang, Zhifang
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 22.01.2020
• Subjects: Avian leukosis virus subgroup J; Dominant variants; Follicle; Vertical transmission; Follicle; Vertical transmission; Dominant variants; Avian leukosis virus subgroup J
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2019.11.042

Avian leukosis virus (ALV) is one of the main causative agent of tumor development, which brings enormous economic losses to the poultry industry worldwide. ALV can be transmitted horizontally and vertically, and the latter often give rise to more adverse pathogenicity. However, the propagation and evolution of ALV underlying vertical transmission remain not-well understood. Herein, an animal model for the evolution of variants of ALV subgroup J (ALV-J) in the vertical transmission was built and different organs from infected hens and plasma from their ALV-positive progenies were collected, and then three segments in the hypervariable regions of ALV (gp85-A, gp85-B, LTR-C) were amplified and sequenced using conventional Sanger sequencing and MiSeq high-throughput sequencing, respectively. The results showed that the genomic diversity of ALV-J occurred in different organs from ALV-J infected hen, and that the dominant variants in different organs of parental hens, especially in follicle, changed significantly compared with original inoculum strain. Notably, the dominant variants in progenies exhibited higher homologies with variants in parental hens’ follicle (88.9%–98.9%) than other organs (85.6%–91.1%), and most consistent mutations in the variants were observed between the progenies and parental hen’s follicle. Furthermore, HyPhy analysis indicated that the global selection pressure value (ω) in the follicle is significantly higher than those in other organs. In summary, an animal model for vertical transmission was built and our findings revealed the evolution of variants of ALV in the process of vertical transmission, moreover, the variants were most likely to be taken to the next generation via follicle, which may be related to the higher selection pressure follicle underwent. •An animal model for vertical transmission of ALV-J was built.•Significant differences of the dominant variants of gp85-B were observed between follicle and other organs of parental hens.•The dominant variants in the progeny had higher homology with that in the follicle of the parental hens.