Don Y. Huang

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It has been reported that the polypeptide of thymidine kinase type 1 (TK1) from human and mouse cells can be modified by phosphorylation. Our laboratory has further shown that the level of human TK phosphorylation increases during mitotic arrest in different cell types (Chang, Z.-F., Huang, D.-Y., and Hsue, N.-C. (1994) J. Biol. Chem. 269:21249-21254). In(More)
The expression of cytosolic human thymidine kinase (TK) occurs in a cell cycle-dependent manner. Here, we show that TK is hyperphosphorylated during the M phase in several human cell lines. Our data from characterizing TK phosphorylation in proliferating and M phase-arrested HeLa cells suggest that the polypeptide of TK is differentially phosphorylated(More)
Presence of homo- and hetero-tetrameric rice sucrose synthase (RSS) isoforms in etiolated rice seedlings was demonstrated by immunoprecipitation using monospecific antibodies. Three RSS isozymes with various pI values were purified by ammonium sulfate fractionation, Sepharose CL-6B gel filtration, DEAE-Sephacel and Mono-Q ion exchange chromatographies. They(More)
As human diploid fibroblasts (HDFs) in culture senesce, the expression of thymidine kinase (TK) and the activity of its promoter become attenuated. Herein we analyze the cis-elements involved in transcriptional activation of the hTK promoter, and show that the Sp1 binding site located at -118/-113 and one CCAAT box located at either -71/-67 or -40/-36 are(More)
Transcriptional activation of the human thymidine kinase (hTK) promoter plays an important role in the cell cycle control of thymidine kinase expression. Using the luciferase reporter cotransfection assay, we found that the activity of the hTK promoter in IMR-90 normal human diploid fibroblasts was increased by the constitutively over-expressed cyclin A or(More)
Transcriptional activation is important for the elevated expression of human thymidine kinase (hTK) in tumor cells. Here, we used TK(-133/+33)-luciferase reporter gene construct and bandshift assay to study the cis-elements involved in transcriptional activation of the hTK promoter. We found that two CCAAT boxes at -71/-67 and -40/-36 and Sp1 binding site(More)
It has been well established that the regulation of thymidine kinase (TK) expression is highly growth-dependent. In this report, we present evidence that TK expression in undifferentiated HL-60 cells is not stringently controlled in a growth-dependent manner, except for a very moderate activation of TK in response to growth stimulation. Moreover, we have(More)
The overexpression of the cyclin-dependent kinase (CDK) inhibitor p21(Waf1) can inhibit cell proliferation, which is mediated by direct binding to CDK and proliferating-cell nuclear antigen. In this study, we demonstrated that human cytosolic thymidine kinase 1 (TK1) polypeptide can form a complex with p21(Waf1). The C-terminal domain of p21(Waf1) appeared(More)
With the reorganization of the grassroots structure and economic readjustment, the commune- and brigade-run plants have now been changed to district (town)- and village-run plants, respectively, and the role of industrial production has become more important to the total income of the people. The Qi-yi Commune (District) is a good example. The number of(More)