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)

Although the in vivo effect of estrogen on myometrial differentiation is well documented, estrogen effects on primary myocytes in vitro have been difficult to demonstrate. To construct a stable uterine myocyte system, capable of direct estrogen responsiveness, we used a transformed hamster myometrial cell line. Since these cells expressed a low level of estrogen receptors (ERs), we have stably transfected them with a vector for the human ER. After transfection, ER concentration increased from less than 300 sites per cell to 17,000 +/- 2,000 sites per cell (mean +/- SEM). To test the functional integrity of the transfected receptors, a chloramphenicol acetyltransferase gene linked to an estrogen response element upstream of thymidine kinase promoter was transiently transfected, and the amount of chloramphenicol acetyltransferase activity, an indicator of estrogen responsiveness, was found to increase 20-fold in response to 17 beta-estradiol (1 nM for 48 h). Furthermore, we tested the ability of estrogen to activate endogenous genes by measuring progesterone receptor (PR) induction. PR concentration in the transfected cells was 3,700 +/- 800 and increased 9-fold to 33,000 +/- 6,000 with 17 beta-estradiol (2 nM). This receptor density increase was confirmed by immunoblotting. PR induction was maximal at 16 h, was concentration dependent, and was not elicited by tamoxifen or ICI 164,384. We conclude that transformed hamster myocytes transfected with an ER gene are capable of estrogen-dependent PR expression in vitro and may serve as a useful system to study estrogen effect on myocytes.
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PMID:Restoration of estrogen-dependent progesterone receptor expression in a uterine myocyte cell line. 846 59

Noninvasive serial monitoring of the fate of transplanted cells would be invaluable to evaluate the potential therapeutic use of human hepatocyte transplantation. Therefore, we assessed the feasibility of bioluminescent imaging using double or triple fusion lentiviral vectors in a NOD-SCID mouse model transplanted with immortalized human fetal hepatocytes. Lentiviral vectors driven by the CMV promoter were constructed carrying reporter genes: firefly luciferase and green fluorescence protein with or without herpes simplex virus type 1 thymidine kinase. Human fetal hepatocytes immortalized by telomerase reconstitution (FH-hTERT) were successfully transduced with either of these fusion vectors. Two million stably transduced cells selected by fluorescence-activated cell sorting were injected into the spleens of NOD-SCID mice pretreated with methylcholanthrene and monocrotaline. The transplanted mice were serially imaged with a bioluminescence charged-coupled device camera after D-luciferin injection. Bioluminescence signal intensity was highest on day 3 (6.10 +/- 2.02 x 10(5) p/s/cm2/sr, mean +/- SEM), but decreased to 2.26 +/- 1.54 x 10(5) and 7.47 +/- 3.09 x 10(4) p/s/cm2/sr on day 7 and 10, respectively (p = 0.001). ELISA for human albumin in mice sera showed that levels were similar to those of control mice on day 2 (3.25 +/- 0.92 vs. 2.84 +/- 0.59 ng/ml, mean +/- SEM), peaked at 18.04 +/- 3.11 ng/ml on day 7, and decreased to 8.93 +/- 1.40 and 3.54 +/- 0.87 ng/ml on day 14 and 21, respectively (p = 0.02). Real-time quantitative RT-PCR showed gene expression levels of human albumin, alpha1-antitrypsin, and transferrin in mouse liver were 60.7 +/- 6.5%, 26.0 +/- 1.4%, and 156.8 +/- 62.4% of those of primary human adult hepatocytes, respectively, and immunohistochemistry revealed cells with human albumin and alpha1-antitrypsin expression in the mouse liver. In conclusion, our study demonstrated that bioluminescent imaging appears to be a sensitive, noninvasive modality for serial monitoring of transplanted hepatic stem cells.
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PMID:Use of bioluminescent imaging to assay the transplantation of immortalized human fetal hepatocytes into mice. 1906 33