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Title: COMPARISON OF CHINESE FIELD STRAINS OF J-SUBGROUP AVIAN LEUKOSIS VIRUSES WITH BRITAIN PROTOTYPE STRAIN HPRS103 AND AMERICAN STRAINS FOR THEIR ENVELOPE PROTEIN AND 3'UTR SEQUENCES

Author
item CUI, ZHIZHONG - SHANDONG AGRIC UNIV PRC
item DU, YAN - SHANDONG AGRIC UNIV PRC
item ZHANG, ZHI - SHANDONG AGRIC UNIV PRC
item Silva, Robert

Submitted to: Chinese Journal of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Subgroup J avian leukosis virus (ALV-J) induces a cancer-like disease in chickens. This virus has caused considerable problems in the U.S. commercial poultry industry and has begun spreading worldwide. It is currently believed that all the known ALV-Js in the U.S. and England arose from a single mutation event. The objective of this research was to determine how related the ALV- Js isolated in the People's Republic of China are to the ALV-Js isolated from poultry farms in the U.S. We isolated five strains of ALV-J from various infected chickens in China. When we determined the unique arrangements (sequence) of the genetic building blocks (DNA bases) of the viruses, we found that all the Chinese isolates contained the same genetic modification that only occurred in one unique U.S. isolate. Thus, a single mutational event, thought to have given rise to the virus we call ALV-J, has resulted in a virus that has spread around the world. The information will help scientists in academia and industry to understand the basis for ALV-J mutation, an essential factor in developing more effective methods for control of this economically important viral infection of meat-type chickens.

Technical Abstract: Five Chinese field strains of subgroup J avian leukosis viruses (ALV-J) were isolated from broiler slaughters or suspected dead broiler breeders in 1999 and 2000. One of them, SD9902, was an acutely transforming virus and able to induce typical myelocytomatosis in 22-38 days after inoculation of 1-day-old meat-type chicks. Their envelope protein and 3'UTR were compared with the Britain prototype HPRS103 and several American field strains isolated in 1993-1997. All Chinese strains have the almost same deletions as the American strain 4817 in "E" element region of 3'UTR when compared to prototype HPRS103, indicating that they have a very close phylogenic relation and the "E" element may not be necessary to the acute transforming ability of ALV-J. Every year, China has to import grandparent breeders of meat-type chickens, mainly from the United States. Chinese isolates should represent a part in the phylogenic tree of U.S. ALV-J evolution. Envelope protein amino acid sequence analysis demonstrated that, interestingly, all recent Chinese isolates were more closely related to HPRS-103 and early U.S. isolates but drifted away from the late U.S. isolates. The result implies that envelope proteins may not necessarily further diverse from their progenitors during the evolution.