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

By means of metaphase chromosomes, the genes for mink thymidine kinase (TK) and hypoxanthine-phosphoribosyltransferase (HPRT) were transferred to mutant mouse cells, LMTK-, A9 (HPRT-) and teratocarcinoma cells, PCC4-aza 1 (HPRT-). Eighteen colonies were isolated from LMTK- (series A), 9 from A9 (series B) and none from PCC4-aza 1. The transformed clones contained mink TK or HPRT. Analysis of syntenic markers in series B demonstrated that one clone contained mink glucose-6-phosphate dehydrogenase (G6PD) and the other alpha-galactosidase; in series A, nine clones contained mink galactokinase (GALK) and six mink aldolase C (ALDC). Analysis of 12 asyntenic markers located in ten mink chromosomes showed the presence of only aconitase-1 (ACON1) (the marker of mink chromosome 12) in three clones of series A. The clones lost mink ACON1 between the fifth to tenth passages. Cytogenetic analysis established the presence of a fragment of mink chromosome 8 in eight clones of series A, but not in series B. The clones of series A lost mink TK together with mink GALK and ALDC during back-selection; in B, back-selection retained mink G6PD. No stable TK+ phenotype was detected in clones with a visible fragment of mink chromosome 8. Stability analysis demonstrated that about half of the clones of series B have stable HPRT+ phenotype whereas only three clones of series A have stable TK+ phenotype. It is suggested that the recipient cells, LMTK- and A9, differ in their competence for genetic transformation and integration of foreign genes.
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PMID:Cotransfer and phenotypic stabilisation of syntenic and asyntenic mink genes into mouse cells by chromosome-mediated gene transfer. 659 20

Retrovirus vectors were constructed to transfer and express the cDNA of the human lysosomal acid hydrolase beta-glucuronidase (GUSB) under control of the human GUSB promoter. Expression of the transcription unit (minigene) was evaluated in a GUSB-negative cell line established from a mouse with the lysosomal storage disease mucopolysaccharidosis (MPS) type VII. A vector designed to transfer single copies of the minigene (N2H beta H) expressed normal levels of GUSB activity in the deficient cells. GUSB expression was increased to several times greater than normal by inserting the minigene into a double-copy vector (DCH beta H), which places one copy of the transcription unit upstream of the retrovirus promoter in both the 3' and 5' long terminal repeats (LTRs) of the integrated provirus. The specific activity of GUSB and a control normal lysosomal enzyme, alpha-galactosidase (GLA), were higher in normal and in vector-corrected cells from confluent cultures than in subconfluent dividing cells. The ratios of GUSB to GLA were similar at all phases of cell growth, but the level of GUSB expression from the double copy vector was several-fold higher than from the single copy vector. To determine if this effect was controlled by the GUSB promoter, a vector was constructed using the thymidine kinase (TK) promoter to drive the human GUSB cDNA (NTK beta H). The levels of GUSB in cells corrected with this vector exhibited the same cell density dependent pattern as when the GUSB promoter was used, indicating that the variation in enzymatic activity was not a function of the GUSB promoter.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:High level expression and export of beta-glucuronidase from murine mucopolysaccharidosis VII cells corrected by a double-copy retrovirus vector. 771 36