Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001486 (Adenovirus)
 3,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenovirus requires the virus-encoded single-stranded DNA-binding protein (DBP) to replicate its DNA. We have previously shown (M. Tsuji, P. C. van der Vliet, and G. R. Kitchingman, J. Biol. Chem. 266:16178-16187, 1991) that the inability of three temperature-sensitive (ts) mutant DBPs (Ad2+ ND1ts23, Ad2ts111A, and Ad5ts125) to support DNA replication at the nonpermissive temperature was associated with impaired ability to bind to DNA. In this study, we examined these mutant proteins for structural alterations that might be linked to the functional changes. All three ts mutants, but not the wild-type protein, showed different proteolytic cleavage patterns before and after heating at 40 degrees C (the nonpermissive temperature), suggesting a possible conformational change during heating. The Ad2+ND1ts23 and Ad2ts111A DBPs have single amino acid changes located in a putative zinc finger subdomain (positions 282 and 280). In the presence of zinc ions, these ts mutants showed significantly increased resistance to inactivation at 40 degrees C. Surprisingly, however, the stabilizing effect of zinc was also observed with the Ad5ts125DBP, which contains a mutation located more than 100 amino acids from the zinc finger. Other related metal ions, such as cobalt, cadmium, and mercury, did not protect the ts DBPs from inactivation at 40 degrees C. These results indicate that functional changes of the ts DBPs in DNA replication and DNA binding are accompanied by structural alterations in the protein and that zinc and the metal-binding subdomain may play an important role in the structure and/or function of the DBP.
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PMID:Functional changes in temperature-sensitive mutants of the adenovirus single-stranded DNA-binding protein are accompanied by structural alterations. 153 Jul 72

Aphidicolin is a highly specific inhibitor of DNA polymerase alpha and has been most useful for assessing the role of this enzyme in various replication processes (J. A. Huberman, Cell 23:647-648, 1981). Both nuclear DNA replication and simian virus 40 DNA replication are highly sensitive to this drug (Krokan et al., Biochemistry 18:4431-4443, 1979), whereas mitochondrial DNA synthesis is completely insensitive (Zimmerman et al., J. Biol. Chem. 255:11847-11852, 1980). Adenovirus DNA replication is sensitive to aphidicolin, but only at much higher concentrations. These patterns of sensitivity are seen both in vivo and in vitro (Krokan et al., Biochemistry 18:4431-4443, 1979). A temperature-sensitive mutant of adenovirus type 5 known as H5ts125 is able to complete but not initiate new rounds of replication at nonpermissive temperatures (P. C. van der Vliet and J. S. Sussenbach, Virology 67:415-426, 1975). When cells infected with H5ts125 were shifted from permissive (33 degrees C) to nonpermissive (41 degrees C) conditions, the residual DNA synthesis (elongation) showed a striking increase in sensitivity to aphidicolin. The temperature-sensitive mutation of H5ts125 is in the gene for the 72-kilodalton single-stranded DNA-binding protein. This demonstrated that the increased resistance to aphidicolin shown by adenovirus DNA replication was dependent on that protein. It also supports an elongation role for both DNA polymerase alpha and the 72-kilodalton single-stranded DNA-binding protein in adenovirus DNA replication. Further support for an elongation role of DNA polymerase alpha came from experiments with permissive temperature conditions and inhibiting levels of aphidicolin in which it was shown that newly initiated strands failed to elongate to completion.
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PMID:Resistance of adenoviral DNA replication to aphidicolin is dependent on the 72-kilodalton DNA-binding protein. 680 58