Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exosomes are small membranous microvesicles (40-100 nm in diameter) and are extracellularly released from a wide variety of cells. Exosomes contain microRNA, mRNA, and cellular proteins, which are delivered into recipient cells via these exosomes, and play a role in intercellular communication. In bovine leukemia virus (BLV) infection of cattle, although it is thought to be a minor route of infection, BLV can be transmitted to calves via milk. Here, we investigated the association between exosomes and BLV in bovine milk. BLV structural proteins, gp51 (Env) and p24 (Gag), were detected in bovine milk exosomes from BLV-infected cattle by Western blot analysis. In cells inoculated with these milk exosomes, BLV DNA was not detected during three serial passages by nested PCR. Purification of exosomes from persistently BLV-infected cells was achieved by immuno-magnetic separation using an antibody against exosomes coupled to magnetic beads. Consistently, BLV gp51 and p24 proteins were detected in purified exosomes. Moreover, reverse transcriptase activity was observed in purified exosomes, meaning that exosomes also contain viral enzyme. However, BLV DNA was not detected in serially passaged cells after inoculation of purified exosomes, indicating that exosomes carrying BLV proteins appeared to be not infectious. These results suggest that BLV proteins are released with milk exosomes and could be transferred into recipient cells of calves via milk exosomes as an alternative route not requiring virus infection. Moreover it is also possible that bovine milk exosomes play a role in clearance of BLV proteins from infected cells.
...
PMID:Cell Infectivity in relation to bovine leukemia virus gp51 and p24 in bovine milk exosomes. 2414 82

Genetic peculiarities of bovine leukemia virus isolates (BLV) spread throughout Russia and Ukraine (BLV-1, BLV-2, and BLV-4) have been characterized based on pol gene polymorphism. Seven viral forms have been detected. The variability of BLV isolates did not exceed 1% within one form. Despite the recent inhabitation of BLV in Russia in the middle of 20th century, Russian BLV variants are characterized by several specific nucleotide substitutions. Point mutations that result in the changes in the aminoacid sequence of reverse transcriptase of BLV specific to distinct viral forms were observed. C --> G transition at the 2752 position (relatively to the reference genome AF033818), which results in the substitution of glutamic to asparaginic acid (GAG --> GAC), is specific to form BLV-2. This mutation was demonstrated in BLV isolates from Ukraine. The T --> G substitution at the 2758 position, which results in the substitution of isoleucine for methionine (ATT --> ATG), is specific to BLV-4 and BLV-7 forms. The BLV-4 form was only detected in Russia and Ukraine. The present study also includes a review of the published data concerning BLV variability. The existing classifications of BLV forms have been critically conceived and the new optimal classification of BLV forms with the maximal resolution has been suggested.
 ...
PMID:[Specific genetic features of the Russian forms of bovine leukemia virus]. 2547 84

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis (EBL), to which animals are most susceptible at 4-8 years of age. In this study, we examined tumor cells associated with EBL in an 18-year-old cow to reveal that the cells carried at least two different copies of the virus, one of which was predicted to encode a reverse transcriptase (RT) lacking ribonuclease H activity and no integrase. Such a deficient enzyme may exhibit a dominant negative effect on the wild-type RT and cause insufficient viral replication, resulting in delayed tumor development in this cow.
 ...
PMID:Delayed-onset enzootic bovine leukosis possibly caused by superinfection with bovine leukemia virus mutated in the pol gene. 2602 55


<< Previous 1 2 3 4 5