scholarly journals Streptococcus gordonii Strains Resistant to Fluorodeoxyuridine Contain Mutations in the Thymidine Kinase Gene and Are Deficient in Thymidine Kinase Activity

2000 ◽  
Vol 44 (3) ◽  
pp. 787-789 ◽  
Author(s):  
C. A. Franke ◽  
T. M. Bolman ◽  
S. A. Ottum ◽  
K. F. Jones ◽  
D. E. Hruby
Keyword(s):  
Thymidine Kinase ◽  
Kinase Activity ◽  
In Vitro Translation ◽  
Streptococcus Gordonii ◽  
Thymidine Kinase Gene ◽  
Thymidine Kinase Activity ◽  
Kinase Gene ◽  
Reading Frame ◽  
Coding Regions

ABSTRACT Mutants of Streptococcus gordonii resistant to 5-fluorodeoxyuridine (FUdRr) were isolated. Each strain contained a point mutation resulting in the premature termination of the thymidine kinase (TK) open reading frame (tdk). In vitro translation of the mutant tdkcoding regions resulted in synthesis of truncated TK polypeptides deficient in TK activity.

scholarly journals Translational Compensation of a Frameshift Mutation Affecting Herpes Simplex Virus Thymidine Kinase Is Sufficient To Permit Reactivation from Latency

2003 ◽  
Vol 77 (8) ◽  
pp. 4703-4709 ◽  
Author(s):  
Anthony Griffiths ◽  
Shun-Hua Chen ◽  
Brian C. Horsburgh ◽  
Donald M. Coen
Keyword(s):  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Kinase Activity ◽  
Thymidine Kinase Gene ◽  
Ribosomal Frameshift ◽  
Thymidine Kinase Activity ◽  
Kinase Gene ◽  
Low Levels ◽  
Simplex Virus ◽  
Low Activity

ABSTRACT Herpes simplex virus thymidine kinase is important for reactivation of virus from its latent state and is a target for the antiviral drug acyclovir. Most acyclovir-resistant isolates have mutations in the thymidine kinase gene; however, how these mutations confer clinically relevant resistance is unclear. Reactivation from explanted mouse ganglia was previously observed with a patient-derived drug-resistant isolate carrying a single guanine insertion within a run of guanines in the thymidine kinase gene. Despite this mutation, low levels of active enzyme were synthesized following an unusual ribosomal frameshift. Here we report that a virus, generated from a pretherapy isolate from the same patient, engineered to lack thymidine kinase activity, was competent for reactivation. This suggested that the clinical isolate contains alleles of other genes that permit reactivation in the absence of thymidine kinase. Therefore, to establish whether thymidine kinase synthesized via a ribosomal frameshift was sufficient for reactivation under conditions where reactivation requires this enzyme, we introduced the mutation into the well-characterized strain KOS. This mutant virus reactivated from latency, albeit less efficiently than KOS. Plaque autoradiography revealed three phenotypes of reactivating viruses: uniformly low thymidine kinase activity, mixed high and low activity, and uniformly high activity. We generated a recombinant thymidine kinase-null virus from a reactivating virus expressing uniformly low activity. This virus did not reactivate, confirming that mutations in other genes that would influence reactivation had not arisen. Therefore, in strains that require thymidine kinase for reactivation from latency, low levels of enzyme synthesized via a ribosomal frameshift can suffice.

scholarly journals Role of the promoter in the sensitivity of human thymidine kinase to lack of Zn2+

1995 ◽  
Vol 308 (2) ◽  
pp. 659-664 ◽  
Author(s):  
J K Chesters ◽  
R Boyne ◽  
L Petrie ◽  
K E Lipson
Keyword(s):  
Binding Site ◽  
Thymidine Kinase ◽  
Transcription Initiation ◽  
Kinase Activity ◽  
Initiation Site ◽  
Specific Protein ◽  
Thymidine Kinase Gene ◽  
Thymidine Kinase Activity ◽  
Kinase Gene

Previous studies had indicated that lack of Zn2+ inhibits the expression of thymidine kinase activity and produces a corresponding reduction in the concentration of its mRNA. The present investigations have shown that with human thymidine kinase this is associated with increased binding of a specific protein to the gene's promoter in the region between -55 and -83 bp 5′ to the transcription initiation site. A second binding site for the protein is present within the sixth exon of the human thymidine kinase gene.

Expression of complete chicken thymidine kinase gene inserted in a retrovirus vector

1984 ◽  
Vol 4 (4) ◽  
pp. 749-754
Author(s):  
P K Bandyopadhyay ◽  
H M Temin
Keyword(s):  
Long Terminal Repeat ◽  
Thymidine Kinase ◽  
Rna Synthesis ◽  
Kinase Activity ◽  
Terminal Repeat ◽  
Thymidine Kinase Activity ◽  
Opposite Orientation ◽  
Kinase Gene ◽  
Intervening Sequences ◽  
High Level

The chicken thymidine kinase (tk) gene was inserted into spleen necrosis virus. Thymidine kinase activity was expressed even when the promoter and terminator sequences for tk RNA synthesis were retained. When the promoter was present in the same orientation as the promoter in the long terminal repeat of the virus, deletions occurred both in the virus and in the tk gene, and the thymidine kinase-transforming activity of the recovered virus was low. Splicing of apparent intervening sequences in the tk gene was also observed. When the orientation of the tk promoter was opposite to the promoter in the long terminal repeat, virus synthesis was diminished, whereas thymidine kinase activity was expressed at an elevated level compared with virus in which the promoter was in the same orientation. However, when the apparent tk promoter was deleted from virus with the tk gene in the opposite orientation, a high level of virus synthesis was observed, probably as a result of absence of interference of RNA synthesis from converging promoters. The intervening sequences in the virus in which the promoters were in opposite orientation were not spliced.

Mutant strains of Tetrahymena thermophila defective in thymidine kinase activity: biochemical and genetic characterization

1982 ◽  
Vol 2 (8) ◽  
pp. 930-938
Author(s):  
K V Cornish ◽  
R E Pearlman
Keyword(s):  
Thymidine Kinase ◽  
Kinase Activity ◽  
Tetrahymena Thermophila ◽  
Permissive Temperature ◽  
Thymidine Kinase Activity ◽  
Cell Extracts ◽  
Mutant Strains ◽  
Nucleoside Phosphotransferase

Three mutant strains, one conditional, of Tetrahymena thermophila were defective in thymidine phosphorylating activity in vivo and in thymidine kinase activity in vitro. Nucleoside phosphotransferase activity in mutant cell extracts approached wild-type levels, suggesting that thymidine kinase is responsible for most, if not all, thymidine phosphorylation in vivo. Thymidine kinase activity in extracts of the conditional mutant strain was deficient when the cells were grown or assayed or both at the permissive temperature, implying a structural enzyme defect. Analysis of the reaction products from in vitro assays with partially purified enzymes showed that phosphorylation by thymidine kinase and nucleoside phosphotransferase occurred at the 5' position. Genetic analyses showed that the mutant phenotype was recessive and that mutations in each of the three mutant strains did not complement, suggesting allelism.

18F-FEAU as a radiotracer for herpes simplex virus thymidine kinase gene expression: in-vitro comparison with other PET tracers

2006 ◽  
Vol 27 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Anne Rixt Buursma ◽  
Vera Rutgers ◽  
Geke A.P. Hospers ◽  
Nanno H. Mulder ◽  
Willem Vaalburg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Thymidine Kinase Gene ◽  
Kinase Gene ◽  
Pet Tracers ◽  
Simplex Virus ◽  
In Vitro Comparison
Sign in / Sign up

Export Citation Format

Share Document