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

A noncytopathic type 1a bovine viral diarrhea virus (BVDV) was isolated from a free-ranging yearling female mule deer (Odocoileus hemionus) from northwestern Wyoming (USA). The mule deer was emaciated, weak, and salivating, and Arcanobacterium pyogenes was cultured from lung abscesses. Bovine viral diarrhea virus was isolated from lung, however, BVDV antigen was not detected by immunohistochemistry. The BVDV genotype was determined by reverse transcriptase polymerase chain reaction and the RNA sequences from the 5'UTR and E2 genes compared with sequences of a type 1a BVDV isolated from cattle from the same area as the deer. The sequences from the deer BVDV were distinct from those of the bovine type 1a BVDV, but similar to other bovine type 1a BVDVs. Seventy-four (60%) of 124 sera collected from mule deer in this area had serum neutralizing antibody titers to type 1a BVDV of > or = 1:32. The high prevalence of seropositive mule deer and isolation of BVDV suggests that this virus circulates in the mule deer population. The isolate described in this report is the second reported BVDV isolate from free-ranging deer in North America and the first from a mule deer.
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PMID:Isolation of bovine viral diarrhea virus from a free-ranging mule deer in Wyoming. 1131 Aug 81

Bovine viral diarrhea virus (BVDV) is amongst the best-characterized members of the Flaviviridae, that includes the hepatitis C virus (HCV). The virally encoded RNA-dependent RNA polymerase (RdRp) plays a crucial role during replication and therefore represents an important target for the development of antiviral drugs. Here we studied biochemical mechanisms associated with the inhibition of BVDV RNA synthesis by 2'-hydroxyl, 3'-deoxynucleoside triphosphates (3'-dNTPs). All four nucleotide analogues are effectively incorporated and act as chain-terminators. However, relatively low, physiologically relevant concentrations of pyrophosphate (PPi) are sufficient to drive the reaction backwards, which results in primer unblocking and rescue of RNA synthesis. Metal ion requirements for nucleotide incorporation and pyrophosphorolysis are similar; the efficiency of both reactions is higher with Mn2+ as compared to Mg2+. Complexes containing chain-terminated primer strands are stable in the presence of heparin, which increases the probability that pyrophosphorolysis occurs before the enzyme can dissociate from its nucleic acid substrate. In contrast to the reverse transcriptase of the human immunodeficiency virus type-1 (HIV-1 RT), the BVDV RdRp may not recruit NTP pools as PPi donors. Conversely, we found that the efficiency of primer unblocking is severely compromised in the presence of increasing concentrations of the NTP that is complementary to the next template position. These data suggest that the incoming NTP can access its designated binding site, which, in turn, prevents the catalytically competent complexation of PPi. The results of this study provide novel insights into mechanisms involved in pyrophosphorolysis associated with viral RdRps, and suggest that the excision reaction is likely to be an important parameter that can affect susceptibility to nucleotide analogue inhibitors directed against viral RdRps.
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PMID:Excision of incorporated nucleotide analogue chain-terminators can diminish their inhibitory effects on viral RNA-dependent RNA polymerases. 1500 48

Bovine viral diarrhea virus (BVDV) is a significant pathogen associated with gastrointestinal, respiratory, and reproductive diseases of cattle worldwide. It causes continuous economic losses to the cattle industry primarily due to decreased reproductive performance. The ability of virus to cross the placenta during early pregnancy can result in the birth of persistently infected (PI) calves. Persistently infected animals are generally much more efficient transmitters of BVDV than transiently or acutely infected animals because they are capable of shedding large quantities of virus throughout their lives and are considered the primary reservoirs for BVDV. Due to the nature of viral infections, there is no treatment to fully cure an animal of a viral infection. All control programs which are in use in many countries of the world, mainly depend upon the detection of PI animals, eliminating them and preventing their return into the herds. Detection of PI animals at early stage, particularly soon after birth is of significant benefit to implement BVDV control programs. Available diagnostic tests such as virus isolation (VI), immunohistochemistry (IHC), Antigen-Capture ELISA (ACE), and reverse transcriptase polymerase chain reaction (RT-PCR) are used for detection of PI cattle. Each method to detect BVDV has advantages, disadvantages, and applicability for different diagnostic situations. The reliability of diagnostic tests is optimized by choosing the appropriate sampling strategy on the basis of animal age.
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PMID:Persistent bovine viral diarrhea virus (BVDV) infection in cattle herds. 2916 43