Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nucleotide sequence of the 5'-flanking region of the cloned human preproenkephalin A gene, extending to 949 bp upstream of the capping site, has been determined. The preproenkephalin A gene, when joined with an SV40 vector and introduced into COS monkey cells, is efficiently transcribed from its own promoter. To assess the DNA sequence required for promoter function, we have constructed a series of 5'-deletion mutants of a fusion gene that consists of the 949-bp 5'-flanking sequence and capping site of the preproenkephalin A gene and the structural sequence of the herpes simplex virus thymidine kinase gene. The deletions up to 757-172 bp upstream of the capping site exert essentially no effect on the expression of the fusion gene, whereas the deletions up to 145, 111, 81 and 67 bp upstream of the capping site result in a gradual decrease in the transcriptional efficiency. No detectable amount of the fusion gene transcript is produced with the mutants having deletions up to 67, 43 and 28 bp upstream of the capping site. These results indicate that a functional promoter of the preproenkephalin A gene lies between 67 and 171 bp upstream of the capping site. This promoter region corresponds to a highly GC-rich segment with short repeated sequences and palindromes.
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PMID:Sequence requirement for transcription in vivo of the human preproenkephalin A gene. 632 Nov 55

Estrogen receptor (ER) and thyroid hormone receptors (TRs) are ligand-dependent nuclear transcription factors that can bind to an identical half-site, AGGTCA, of their cognate hormone response elements. By in vitro transfection analysis in CV-1 cells, we show that estrogen induction of chloramphenicol acetyltransferase (CAT) activity in a construct containing a CAT reporter gene under the control of a minimal thymidine kinase (tk) promoter and a copy of the consensus ER response element was attenuated by cotransfection of TR alpha 1 plus triiodothyronine treatment. This inhibitory effect of TR was ligand-dependent and isoform-specific. Neither TR beta 1 nor TR beta 2 cotransfection inhibited estrogen-induced CAT activity, although both TR alpha and TR beta can bind to a consensus ER response element. Furthermore, cotransfection of a mutated TR alpha 1 that lacks binding to the AGGTCA sequence also inhibited the estrogen effect. Thus, the repression of estrogen action by liganded TR alpha 1 may involve protein-protein interactions although competition of ER and TR at the DNA level cannot be excluded. A similar inhibitory effect of liganded TR alpha 1 on estrogen induction of CAT activity was observed in a construct containing the preproenkephalin (PPE) promoter. A study in hypophysectomized female rats demonstrated that the estrogen-induced increase in PPE mRNA levels in the ventromedial hypothalamus was diminished by coadministration of triiodothyronine. These results suggest that ER and TR may interact to modulate estrogen-sensitive gene expression, such as for PPE, in the hypothalamus.
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PMID:Estrogen and thyroid hormone interaction on regulation of gene expression. 890 26

This paper reviews work by Yeomans and Wilson in the area of herpes vector-mediated gene transfer to sensory neurons. Beginning in 1997, these researchers have published a number of papers describing and exploiting this technology in altering the phenotype of pain-sensing neurons (nociceptors). Their initial work, continuing to the present, inserted a transgene cassette encoding the human preproenkephalin gene into the thymidine kinase locus under control of a cytomegalovirus promoter. This vector induced enkephalin expression selectively in the nociceptors innervating the tissue onto which it was applied, producing a profound analgesic and antihyperalgesic in acute and chronic pain models in both rodents and non-human primates. An improved version of this vector is now in clinical trials. In addition to inducing the de novo expression of foreign transgenes, this group also investigated the utility of herpes vectors in altering the endogenous genome of nociceptors. Thus, they inserted antisense sequences for genes of interest in the physiology of these neurons and successfully and selectively knocked down expression of several proteins known or thought to be involved in various pain states, including calcitonin gene-related peptide and mu-opioid receptors. They also used similar techniques to investigate the involvement of acid-sensing ion channels and Nav1.7 sodium channel in different pain states. These experiments uniquely allowed for spatially and temporally selective investigations into the function of these proteins in pain, highly valuable information in target validation for therapy development.
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PMID:Herpes virus-based recombinant herpes vectors: gene therapy for pain and molecular tool for pain science. 1922 46