Analysis of the pX region of bovine leukemia virus in different clinical stages of Enzootic Bovine Leukemia in Argentine Holstein cattle

• Published in: Virus research Vol. 171; no. 1; pp. 97 - 102
• Main Authors: Panei, Carlos Javier, Serena, María Soledad, Metz, Germán Ernesto, Bravi, María Emilia, González, Ester Teresa, Echeverría, María Gabriela
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2013
• Subjects: Amino Acid Substitution; Animals; Argentina; Bovine leukemia virus; Cattle; Clinical stages; Cluster Analysis; disease course; enzootic bovine leukosis; Enzootic Bovine Leukosis - virology; Genes, Regulator; Genes, Viral; Holstein; Leukemia Virus, Bovine - genetics; Molecular Sequence Data; Mutation; polymerase chain reaction; Proviruses - genetics; pX region; regulator genes; Argentina; Clinical stages; Bovine leukemia virus; pX region
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2012.08.001

► We compared the wild-type proviral pXBLV region at different stages of BLV infected Argentine Holstein. ► The proviral pX region of 12 cattle was amplified by PCR. ► This region was sequenced, aligned and compared both with each other and with the reference sequence. ► Applying hierarchical clustering two clusters were obtained, not allowing differentiate by clinical stage. ► We found no amino acid strict differences between the categories of BLV-positive Argentine Holsteins. Bovine leukemia virus (BLV) infection in cattle causes Enzootic Bovine Leukemia (EBL). About 30% of infected cattle develop persistent lymphocytosis (PL), a 0.1–5% develops tumors, and a 70% remains asymptomatic in an aleukemic stage (AL). Regulatory genes of BLV (Tax, Rex, R3 and G4) are located in a region known as pXBLV. The variability of those genes had been postulated with the progression of the disease. The aim of this work was to compare the wild-type proviral pXBLV region at different stages of BLV natural infected cattle from Argentine Holstein. Pairs of primers were designed to amplify the proviral pX region of 12 cattle by PCR, and products were then sequenced, aligned and compared both with each other and with the reference sequence. Results show a divergence percentage from 0 to 6.1 for the Tax gene, from 0 to 9.4% for the Rex gene, from 0 to 12.1% for the R3 gene and finally from 0 to 6.5% for the G4 gene. Results obtained with hierarchical clustering showed two clusters well differentiated, where the members of each cluster are cattle that had tumor, PL and AL, not allowing differentiate those two cluster by clinical stage.