Xiongyan LIANG, Lan LIU, Chun FANG, Yufang GU, Tuofan LI, Yuying YANG

Identified Novel Deletions in the Genomes of Avian Endogenous Retroviruses ev/J in Chicken Breeds in China

Avian leukosis virus subgroup J (ALV-J) infection can cause tumors and immunosuppression, which has made huge financial loss in the poultry industry. More and more new pathogenic avian leukosis virus, which were recombined from exogenous avian leukosis virus and endogenous retrovirus viruses were isolated from China and other regions in the world. To uncover the characteristic of the potential recombinant elements, we analyzed the genomes of avian endogenous retrovirus ev/J in ten chicken breeds in China. Six of the ten chicken breeds contained two sizes of ev/J (3.8 kb and 2.2 kb) and the other only contained 3.8 kb ev/J. The ten 3.8 kb ev/J were much closer to type I, II and III ev/J prototypes, while the six 2.2 kb ev/J were close to type IV ev/J prototype in the phylogenetic trees. Moreover, three novel deletion fragments were identified in the sixteen ev/J in chicken flocks in China, which made most of the ev/J (10/16) significantly different from the four ev/J prototypes. The emergence of these novel deletions resulted in the diversity of ev/J in chicken breeds in China, which may become the source of further recombination of avian leukosis viruses (ALVs), especially the exogenous ALV subgroup J.

Çin’de Tavuk Cinsleri Arasında Avian Endojen Retrovirus ev/J Genomunda Yeni Delesyonların Tespiti

Avian lökozis virus subgroup J (ALV-J) enfeksiyonu tümör ve immunosuprasyona neden olarak kanatlı sektöründe önemli finansal kayıpların oluşmasına yol açabilir. Eksojen avian lökozis virus ve endojen retroviruslardan rekombine edilen yeni patojenik avian lökozis viruslar her gün Çin ve dünyanın diğer bölgelerinden izole edilmektedir. Potansiyel rekombinant elementlerin özelliklerini açığa çıkarmak amacıyla Çin’de on farklı tavuk cinsinden avian endojen retrovirus ev/J’nin genomları analiz edildi. On cinsten altısında iki farklı ev/J büyüklüğü (3.8 kb ve 2.2 kb) tespit edilirken diğerlerinde sadece 3.8 kb ev/J mevcuttu. Filogenetik ağaçta on 3.8 kb ev/J tip I, II ve III ev/J prototiplerine çok daha yakın iken altı 2.2 kb ev/J ise tip IV ev/J prototipine yakındı. Çin’de on altı tavuk sürüsünde ev/J’de üç yeni delesyon parçacıkları belirlendi. Bu durum çoğu ev/J (10/16)’yi anlamlı derecede dört ev/J prototipinden farklı kılmaktadır. Bu yeni delesyonların meydana gelmesi Çin’de tavuk cinsleri arasında ev/J’de farklılığın oluşmasına neden olarak özellikle eksojen ALV subgrup J olmak üzere avian lökozis viruslarda ileri rekombinasyonların kaynağını oluşturabilir.

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