Title : Bovine leukemia virus tax gene/tax protein and premiRNA genes polymorphism and its relation to Enzootic Bovine Leukosis
Abstract:
The aim of this study is the investigation of the polymorphism of the tax gene/Tax protein and pre-miRs-B (pre-miRNA genes of Bovine leukemia virus (BLV)) polymorphism and its relation to Enzootic Bovine Leukosis.
Methods: Peripheral blood samples of 2 to 5 years old female Holstein cattle (farming in Moscow region, Russia) have been used. They have been tested for proviral DNA host genome insertion by PCR (BLV-positive or BLV-negative) and for the presence of antibodies to gp51 BLV antigen by AGID (BLV-seropositive or BLV-seronegative). All samples have been divided into two groups: the group of 16 BLV-seropositive and proviral BLV-positive samples (further: BLV-positive) and another group of 26 BLV-seronegative and proviral BLV-negative samples (further: BLV-negative). WBCs of the samples have been counted on the Abacus Junior Vet 5 Automatic Hematology Analyzer (Diatron, Austria). The BLV-positive samples group has been used for further investigation of the tax gene/Tax protein and pre-miR-B genes’ polymorphism. DNA fragments of tax and pre-miR-B genes have been amplified and further cloned and sequenced. Five or six clones for each of the BLV-positive samples have been sequenced by Sanger’s method. The t-test (http://www.graphpad.com/quickcalcs/) and ANOVA test (GraphPad Prism V.7.04 (1992–2017 GraphPad Software, Inc.)) have been made for statistical testing of the results.
Results: Several alleles of the tax gene and pre-miR-B genes have been received as proof of its polymorphism. Some of them have a highly significant association with an increase and others – with a decreased number of the WBCs in BLV-infected cows. The specific pre-miR-B alleles can be responsible for the increased number of WBCs in BLV-infected cows. The specific tax alleles (and corresponded Tax protein variants) can be responsible for the decreased number of the WBCs in BLV-infected cows, which could be considered the feature of the aleukemic form of BLV infection. They could be named the aleukemic tax alleles.