Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A fragment of the SIVmac251 pol gene was expressed in Escherichia coli as a trpE fusion protein. Analysis of extracts from bacteria containing this expression plasmid revealed the presence of a reverse transcriptase activity dependent on Mg2+ as divalent cation and active on both poly(rA).oligo(dT) and poly(rC.oligo(dG) templates. In comparative studies, the SIV and HIV-1 reverse transcriptases expressed in bacteria displayed very similar high sensitivities to the chain terminator inhibitors AZTTP and ddTTP. The reverse transcriptase of Moloney murine leukemia virus and the DNA polymerase of E. coli were both more resistant to ddTTP, and the E. coli enzyme was significantly more resistant to AZTTP.
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PMID:Expression of enzymatically active reverse transcriptase of simian immunodeficiency virus in bacteria: sensitivity to nucleotide analogue inhibitors. 170 May 44

Genomic hypermutation of human and simian immunodeficiency viruses (HIV and SIV) enables these viruses to adapt and escape from various types of anti-viral selection by altering the molecular properties of viral gene products. In this study, we examined whether the biochemical and catalytic properties of SIV DNA polymerases (reverse transcriptases; RT) can change during the course of viral infection. For this test, we analyzed RTs obtained from two SIV clones, SIVMNE CL8 and SIVMNE 170. SIVMNE 170 was isolated during the late symptomatic phase of infection with the parental strain, SIVMNE CL8. We found these two RTs have identical DNA polymerase specific activities and kinetics with three different DNA and RNA templates. In addition, the processivity of these two SIV RT proteins were also similar. However, as demonstrated by a misincorporation assay, the SIVMNE 170 RT showed much higher fidelity than SIVMNE CL8. The fidelity difference between these two SIV RTs was also confirmed by a steady state kinetic fidelity assay. These findings suggest that the fidelity of lentiviral RTs may change during the course of viral infection, possibly in response to alterations of host anti-viral immune capability. In addition, our sequence analysis of these two RT genes proposes possible structural strategies that the virus may employ to alter RT fidelity.
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PMID:Identification of a simian immunodeficiency virus reverse transcriptase variant with enhanced replicational fidelity in the late stage of viral infection. 1132 71

Cynomolgus macaques have been widely used as an animal model in preclinical biomedical research and are becoming more popular among HIV/SIV vaccine researchers. Here we report the isolation and characterization of a cytomegalovirus from cynomolgus macaques (CyCMV). CyCMV was isolated from a healthy captive-bred 4-year-old cynomolgus macaque of Filipino origin. The virus was identified by its characteristic growth properties in cell culture, ultrastructural morphology and sequence of viral DNA polymerase and glycoprotein B (gB). CyCMV gB shows 77% identity and 88% homology to rhesus cytomegalovirus (RhCMV) gB and 58% identity and 76% homology to human cytomegalovirus gB at the amino acid level. Phylogenetic analysis using known CMV gB protein sequences show that CyCMV is more closely related to RhCMV than to other primate CMVs. CyCMV down-regulates MHC class I expression on infected cells and we show that the colony-bred cynomolgus macaques have detectable CyCMV-specific humoral and cell-mediated immune responses.
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PMID:Isolation and characterization of cynomolgus macaque (Macaca fascicularis) cytomegalovirus (CyCMV). 2127 7