The radioiodinated thymidine analogue, FIAU, is a tracer that has been developed for reporter gene, for cells that were transfected with herpes simplex virus thymidine kinase, HSV-TK. FIAU is also a specific substrate of bacterial TK due to the homology between viral and bacterial TK. In this issue of AJNMMI (http://www.ajnmmi.us), Pullamb-hatla et al. reported that the accumulation of (125)I-F...

It has been demonstrated that HIV infection may affect the levels of thymidine kinase (TK) and deoxycytidine kinase (dCK) in peripheral blood mononuclear cells from HIV infected adults. The aim of this study was to examine the effect of HIV infection and/or antiretroviral therapy on the activity of the above enzymes in HIV-infected children. The results showed that an inter-individual variabili...

A pseudorabies virus mutant lacking thymidine kinase activity (TK-) was isolated and characterized. The mutant replicated as well in cell culture as the parental TK+ strain, was not temperature sensitive at 38.5 degrees C, and did not revert to TK+. Two pseudorabies virus field isolates and three commercial modified live virus vaccine strains were compared for TK activity and virulence for the ...

Mouse L cells lacking thymidine kinase (Ltk-) that had been transformed to the thymidine kinase-positive (tk+) phenotype by herpes simplex virus type 1 (HSV-1) were cultured in medium containing tritiated thymidine. Six clonal lines of cells surviving this treatment were found to have the following properties: (i) the cells were tk- and had spontaneous back-reversion frequencies to the tk+ phen...

Systems for introducing DNA genes-of-interest into mammalian cellular genomes have ranged from the use of different physical techniques to viruses including retroviruses. We have developed a microinjection method for an efficient and permanent integration of a DNA transgene into the cell genome by use of the retrovirus integrase. A 3.0-kb linear DNA fragment containing an internal herpes simple...

The activation of antiviral drugs as a consequence of thymidine kinase expression has been shown in recent years to have potential as a treatment for malignant tumors. It was hypothesized that the property of the drugs that make them effective against viruses and proliferating cells, namely their ability to interfere with the integrity of the DNA, may be exploited to sensitize cells to radiatio...

background: the organochlorine ddt has estrogenic activity but the mechanism underlying the estrogenic activity of this pesticide remains unclear. in the present investigation here, we studied the transcriptional effects of a synthetic organochlorine pesticide o,p’-ddt [1.1.1.-trichloro-2-(o-chlorophenyl)-2-p-chloriphenyl ethane] and its metabolite p,p'-dde (2-2-bis(4/chlorophenyl)-1-1-dic...

Cytoxicity induced by the herpesvirus thymidine kinase (TK) gene in combination with prodrugs is dependent on cell growth and leads to the elimination of genetically modified cells, thus limiting the duration of expression and efficacy of this treatment in vivo. Here, an effort was made to enhance TK/prodrug efficacy by coexpression of a cyclin-dependent kinase inhibitor (CKI), p27, to render c...

The biological activity of in vitro methylated HSV-TK DNA was analysed after microinjection into thymidine kinase negative rat 2 cells. It was found that the fully methylated DNA (Hpa II methylase) was as active as the non methylated control DNA for about 48 hours after injection. DNA reextraction experiments and blot analysis showed that DNA demethylation was not the reason for the observed TK...

The nucleotide sequences of the coding region of the thymidine kinase (TK) gene of pseudorabies virus strain NIA3 and a TK- mutant (ATK5) were determined. The coding region of the TK gene consists of 320 codons capable of producing a polypeptide with an Mr of 34979. The mutant expressed an inactive TK polypeptide when translated in vitro; a unique base substitution was detected in the mutant TK...