Analysis of Nucleotide Sequence of Tax, miRNA and LTR of Bovine Leukemia Virus in Cattle with Different Levels of Persistent Lymphocytosis in Russia

Abstract

Bovine Leukemia Virus (BLV) is the etiological agent of enzootic bovine leucosis (EBL), a lymphoproliferative disease of the bovine species. In BLV-infected cells, the long terminal repeat (LTR), the viral Tax protein and viral miRNAs promote viral and cell proliferation as well as tumorigenesis. Although their respective roles are decisive in BLV biology, little is known about the genetic sequence variation of these parts of the BLV genome and their impact on disease outcome. Therefore, the objective of this study was to assess the relationship between disease progression and sequence variation of the BLV Tax, miRNA and LTR regions in infected animals displaying either low or high levels of persistent lymphocytosis (PL). A statistically significant association was observed between the A(+187)C polymorphism in the downstream activator sequence (DAS) region in LTR (p-value = 0.00737) and high lymphocytosis. Our study also showed that the mutation (−4)G in the CAP site occurred in 70% of isolates with low PL and was not found in the high PL group. Conversely, the mutations G(−133)A/C in CRE2 (46.7%), C(+160)T in DAS (30%) and A(310)del in BLV-mir-B4-5p, A(357)G in BLV-mir-B4-3p, A(462)G in BLV-mir-B5-5p, and GA(497–498)AG in BLV-mir-B5-3p (26.5%) were often seen in isolates with high PL and did not occur in the low PL group. In conclusion, we found several significant polymorphisms among BLV genomic sequences in Russia that would explain a progression towards higher or lower lymphoproliferation. The data presented in this article enabled the classification between two different genotypes; however, clear association between genotypes and the PL development was not found.

Tracing Viral Transmission and Evolution of Bovine Leukemia Virus through Long Read Oxford Nanopore Sequencing of the Proviral Genome

“…Amino acid analysis of these genomes could increase awareness of BLV pathogenesis and virulence differences among genotypes. Functional changes resulting from mutations in Tax, Rex, and G4-along with multiple other proteins have been previously studied, but do not align with the mutations detected in our sample set [29][30][31][32][33]. More research is needed to see if the amino acid changes listed in Table 3 impact BLV pathogenicity and transmissibility.…”

ELP2‐NLRP3‐GSDMD/GSDME‐mediated pyroptosis is induced by TNF‐α in MC3T3‐E1 cells during osteogenic differentiation

“…Computerized virtual prediction technique is used for simulating protein molecular interactions and predicting binding sites 25 and has been applied to predict protein interactions. 26 , 27 According to previous studies, potential STAT3 binding sites in selected human and mouse genes were predicted using the position weight matrix (PWM) algorithm from TRANSFAC to identify promoter regions, which were defined from the transcriptional start site.…”

Molecular Characterization of Bovine Leukemia Virus with the Evidence of a New Genotype Circulating in Cattle from Kazakhstan

“…The amplification was performed in the Rotor-Gene Q System (Qiagen, Hilden, Germany) using an initial denaturation step and polymerase activation at 95 • C for 15 min, followed by 50 cycles of 94 • C for 60 seconds and 60 • C for 60 s. Tenfold dilutions of pBLV1 plasmid containing 120 bp fragment of pol gene were made from 1 × 10 0 to 1 × 10 5 copies per reaction and used to construct standard curve and estimate the BLV copy numbers. To measure provirus copy number per 1000 cells bovine histone H3 family 3A (H3F3A) gene was amplified by qPCR and ten-fold dilutions of the pDNA from 10 2 to 10 6 copies per µL were used to construct a standard curve [61]. The qPCR was accomplished in a 25 µL final volume containing a mixture of 12.5 µL 2× QuantiTect Multiplex PCR NoROX master mix (Qiagen, Hilden, Germany), 0.4 µM of each primer (Genomed, Warsaw, Poland), 0.2 µM probe, and 500 ng genomic DNA in the Rotor-Gene Q cycler (Qiagen, Hilden, Germany).…”