Post-transcriptional regulation of thymidine kinase gene expression during monocytic differentiation of HL60 promyelocytes.
The regulatory mechanism of human thymidine kinase (TK) gene expression was investigated in HL-60 promyelocytes during induction of monocytic differentiation with 12-O-tetradecanoyl phorbol-13-acetate (TPA). The steady-state levels of TK mRNA diminished gradually as cells were treated with TPA. The nuclear run-on experiments were performed and revealed that TPA treatment did not change TK gene activity in HL-60 cells. These findings suggested that the expression of TK mRNA was controlled by a post-transcriptional mechanism. The half-life of mature TK mRNA transcript was found to be more than 8 hours in both proliferating and differentiated HL-60 cells, which indicated that the stability of mature TK mRNA does not play a role in regulating TK gene expression. Analysis of poly(A-) TK mRNAs showed the high molecular weight precursors of TK mRNA which appeared in proliferating cells were not detectable in TPA-treated cells. This finding suggested that the TK mRNA processing event is implicated in the regulation of human TK gene expression in HL-60 cells during monocytic terminal differentiation.
Chang
Z F
ZF
Department of Biochemistry, Chang Gung Medical College, Tao-Yuan, Taiwan, R.O.C.
D002454:Cell Differentiation; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D015342:DNA Probes; D003609:Dactinomycin / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D005796:Genes; D006801:Humans; D007700:Kinetics; D015473:Leukemia, Promyelocytic, Acute; D009000:Monocytes / Q000166:cytology / Q000201:enzymology; D009693:Nucleic Acid Hybridization; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013937:Thymidine Kinase / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000201:enzymology*
D015342:DNA Probes; D012333:RNA, Messenger; D003609:Dactinomycin; D013937:Thymidine Kinase; D013755:Tetradecanoylphorbol Acetate