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Bovine viral immunodeficiency (BIV), often known as bovine lentivirus, is a disease affecting cattle and buffaloes worldwide. It is caused by the bovine immunodeficiency virus, a member of the Retroviridae family. Once BIV infects animals, it integrates the genome of the host cells and causes a progressive lifelong infection. Despite the record of the virus in various countries, BIV screening in Egyptian animals has never been investigated yet. Therefore, this study aimed to determine whether the BIV provirus was present in blood samples taken from dairy and beef cattle from six provinces in Egypt's northern, central, and southern regions. A total of 310 DNA samples extracted from cattle blood were investigated by the quantitative real-time polymerase chain reaction (qRT-PCR) technique using specific pol gene primers. The findings indicated the absence of BIV provirus in the analyzed samples. The cycle threshold (Ct) values of the tested samples range from 30 - 36.5, while the Ct values of negative control were 29.7 - 36.8. Because of the lack of positive control, UV light visualization of the target amplicon (385 bp) was conducted and revealed no evidence of BIV provirus in the tested samples. Although the investigated animals were grouped according to location, age, sex, breed, production type, and farming system, we could not analyze the potential risk factors because of the negative results in all tested samples. In conclusion, this study presented the first molecular screening of BIV provirus in Egyptian cattle. Additionally, a future large-scale survey on BIV in Egyptian cattle and buffaloes is recommended. [ABSTRACT FROM AUTHOR]

Ancient virus genomes preserved as fossils and carried by host within their genome. Although viral genomes evolve rapidly, their rate of change slows to the same pace as that of the host's DNA after insertion, making it possible to study viral DNA sequences that are many millions of years old. Paleovirology is the study of viral fossil records typically over prehistoric or geological timescales and the effects that these agents have had on the evolution of their hosts. Viruses sometimes heritably integrate into the genomes of their hosts, resulting in genomic features known as endogenous viral elements (EVEs). Using EVEs, the field of paleovirology investigates the long term evolution of viruses and their impact on hosts. One of the fruitful outcomes of high throughput genomics is the widespread availability of whole genome data, offering the unprecedented opportunity to investigate EVEs at a large scale. This review, highlights the utility of antiviral gene evolution for the study of paleovirology, the consequent surge in paleovirology and the main methodological techniques used to study them. EVEs can only be understood within an evolutionary framework and we outline a generalized workflow for conducting paleovirology studies. [ABSTRACT FROM AUTHOR]

The membrane-spanning domain (MSD) of the transmembrane subunit (TM) anchors the envelope glycoprotein (Env) on the lipid bilayer of the host cell membrane and virions. Its functions include membrane fusion efficiency and intracellular trafficking of the lentivirus envelope protein. Our study aimed to determine the MSD of bovine immunodeficiency virus (BIV) glycoprotein 45 (gp45) and reveal structural characteristics of the BIV Env protein. We have predicted the region of the BIV MSD and obtained the sequence using bioinformatics software. Various kinds of assays, including analogy analysis, fluorescence microscopy, and dye-transfer-based assays, were carried out to validate the prediction. The results, for the first time, show that the BIV MSD is located at the D170 to M191 amino acids of gp45, and the identified MSD divides gp45 into the extracellular domain (ED), MSD and cytoplasmic domain (CT). We further found that the BIV MSD had a similar structure and function as the HIV MSD using amino acid sequence alignment and fluorescence microscopy. Additionally, the dye-transfer-based assay demonstrates that deletion of the BIV MSD efficiently decreases cell-cell fusion. Based on the identification of the MSD, a "snorkeling" model, in which the flanking charged amino acid residues are buried in the lipid bilayer while their side chains interact with polar head groups, was proposed for the BIV MSD. Ultimately, we further improved the primary structure of the BIV envelope glycoprotein. [ABSTRACT FROM AUTHOR]

Bovine immunodeficiency is a chronic progressive disease caused by a lentivirus that affects cattle and buffaloes. Although the infection has been described in cattle in some countries, including in Brazil, there are only two reports of infection in buffaloes: one in Pakistan and one in Cambodia. The aim of the present study was to survey the occurrence of bovine immunodeficiency virus (BIV) in water buffaloes from the Amazon region, Pará state, Brazil. BIV proviral DNA was surveyed in 607 whole blood samples of water buffaloes from 10 farms located in the state of Pará using semi-nested polymerase chain reaction (PCR) (PCR-SN) to amplify the pol region of the viral genome. Of the 607 samples tested, 27 (4.4 %) were positive for BIV proviral DNA. The amplified fragments were confirmed by sequence analysis after cloning and nucleotide sequencing. The sequence obtained had 99 % similarity to the reference strain (R-29). The present study provides important epidemiological data because BIV was detected for the first time in water buffaloes in Brazil. Further, the results suggest the possibility of the virus being a risk factor for herd health because it may be a potential causal agent of chronic disease and, also may be associated to other infectious diseases. [ABSTRACT FROM AUTHOR]

The bovine immunodeficiency virus (BIV) is a lentivirus which is known to infect cattle worldwide. Though serological and genomic evidence of BIV in cattle has been found throughout the world, isolation of the virus has been reported only from few places. Very little is known about its impact on animal health status, pathogenesis and mode of transmission. BIV is considered generally non-pathogenic and is not known to cause any serious disease in cattle. BIV is genetically and antigenically related to Jembrana disease virus (JDV), the cause of an acute disease in Bali cattle ( Bos javanicus) and human immunodeficiency virus, the cause of acquired immunodeficiency syndrome in human. Therefore, it is important to monitor the presence of BIV in cattle to keep vigil over its possible evolution in its natural host to emerge as pathogenic lentivirus like JDV. Differentiation of BIV infection in cattle from the acutely pathogenic JDV is important for diagnosis of the latter. Currently, BIV is considered as a safe model for understanding the complex genome of lentiviruses. Further research on BIV is indeed needed to elucidate its possible role in animal health as well as for insight into the molecular mechanisms adopted by related lentiviruses. [ABSTRACT FROM AUTHOR]

Bovine immunodeficiency virus (BIV), a member of the lentivirus subfamily of retroviridae, was originally isolated from a dairy cow with persistent lymphocytosis, lymphoid hyperplasia, and prevascular cuffing in the brain. Serological studies indicated that BIV has worldwide distribution, but its prevalence in Iran is not clearly known. In this investigation, we report the detection of proviral DNA sequence of BIV in 300 blood samples of cattle and 150 blood samples of sheep by polymerase chain reaction (PCR) using oligonucleotiode primers specific for the gag gene region of the virus. Blood samples of cattle and sheep were taken from Chaharmahal Bakhtiary province, Iran. According to the PCR results, infection rate in the cattle and sheep population were 60% and 30%, respectively. This is the first report for the presence of BIV in cattle and sheep population of Chaharmahal Bakhtiary province. [ABSTRACT FROM AUTHOR]

Integrase plays a critical role in the recombination of viral DNA into the host genome. Therefore, over the past decade, it has been a hot target of drug design in the fight against type 1 human immunodeficiency virus (HIV-1). Bovine immunodeficiency virus (BIV) integrase has the same function as HIV-1 integrase. We have determined crystal structures of the BIV integrase catalytic core domain (CCD) in two different crystal forms at a resolution of 2.45 Å and 2.2 Å, respectively. In crystal form I, BIV integrase CCD forms a back-to-back dimer, in which the two active sites are on opposite sides. This has also been seen in many of the CCD structures of HIV-1 integrase that were determined previously. However, in crystal form II, BIV integrase CCD forms a novel face-to-face dimer in which the two active sites are close to each other. Strikingly, the distance separating the two active sites is approximately 20 Å, a distance that perfectly matches a 5-base pair interval. Based on these data, we propose a model for the interaction of integrase with its target DNA, which is also supported by many published biochemical data. Our results provide important clues for designing new inhibitors against HIV-1. [ABSTRACT FROM AUTHOR]

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The inhibition of HIV expression in vitro by a cocktail of the β-chemokines MIP-1α, MIP-1β and RANTES provided the initial evidence that HIV utilizes chemokine receptors as co-receptors for infection of cells. Bovine immunodeficiency virus (BIV), a lentivirus, infects a wide variety of leukocyte populations, but the cellular receptor(s) utilized by this virus for infection of cells is not known. The purpose of this study was to determine whether MIP-1α, MIP-1β and RANTES affect BIV expression in vitro, as a prelude to identifying the cellular receptors utilized by this virus. Fetal bovine lung (FBL) cells were pretreated with serial dilutions of a cocktail of the chemokines, and then the cells were infected with BIV. Virus expression in these cells was determined by counting the syncytia that had developed in the cultures by five days after infection. A significant decrease in syncytium formation, corresponding to increasing concentrations of the chemokines, was the result. Reacting the chemokines with chemokine-specific neutralizing antibodies prior to treatment of the cells neutralized the effect of the chemokines on virus replication in a dose-dependent manner, restoring viral expression to a level similar to that of untreated cells. The presence of a CCR5 homologue on the surface of FBL cells was confirmed using an anti-CCR5 monoclonal antibody and FACS analysis. Collectively, these data provide preliminary evidence that BIV may utilize the CCR5 receptor for infection of cells in vitro, but additional studies are necessary to confirm this. [ABSTRACT FROM AUTHOR]

The association of bovine immunodeficiency virus (BIV) with embryos derived by in vitro fertilization from oocytes of experimentally infected heifers or oocytes/embryos exposed to the virus in vitro was investigated. Using a nested-PCR assay, proviral DNA of BIV was not detected in follicular fluid or in embryos derived from BIV-infected donors. In vitro exposure of oocytes to BIV during maturation or insemination with BIV-infected semen resulted in zona pellucida-intact embryos testing negative for BIV provirus. However, exposure of zona pellucida-free day-7 embryos to the virus resulted in a positive BIV assay for 28% of the batches of embryos, suggesting that the zona pellucida has a role in protecting against BIV infection. The presence of BIV in the IVF system had no apparent effect on the development of bovine embryos to the blastocyst stage. [ABSTRACT FROM AUTHOR]

The arginine-rich RNA-binding domain of bovine immunodeficiency virus (BIV) Tat adopts a ß-hairpin conformation upon binding to the major groove of BIV TAR. Based on its NMR structure, we modeled dimeric arrangements in which two adjacent TAR sites might be recognized with high affinity by a dimeric peptide. Some dimeric RNAs efficiently bound two unlinked BIV Tat peptides in vitro, but could not bind even one monomeric peptide in vivo, as monitored by transcriptional activation of human immunodeficiency virus long terminal repeat reporters. Results with additional reporters suggest that extending the RNA helix in the dimeric arrangements inhibits peptide binding by decreasing major groove accessibility. In contrast, a dimeric peptide efficiently bound an optimally arranged dimeric TAR in vivo, and bound with an affinity at least 10-fold higher than the monomeric peptide in vitro. Mutating specific nucleotides in each RNA 'half-site' or specific amino acids in each ß-hairpin of the dimeric peptide substantially decreased binding affinity, providing evidence for the modeled dimer-dimer interaction. These studies provide a starting point for identifying dimeric RNA-protein interactions with even higher binding affinities and specificities. [ABSTRACT FROM AUTHOR]