Transcriptional regulation of the lactate dehydrogenase A subunit gene by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate.
Regulation of lactate dehydrogenase (LDH) (EC 1.1.1.27) isozymes occurs through a multitude of physiological signals. Here, we show that modulation of LDH A subunit occurs via the protein kinase C pathway. Activators of protein kinase C, such as tetradecanoylphorbol acetate (TPA) and dioctanoylglycerol (DG), caused a 3-4-fold accumulation of LDH A subunit mRNA in rat C6 glioma cells. The specific protein kinase C inhibitor bisindolylmaleimide GF 109203X prevented the TPA-induced increase of LDH A subunit mRNA. To analyze the molecular basis of these effects in more detail, the transcription-modulatory effects of TPA and DG were evaluated in transient transfection assays using plasmids which contain LDH A subunit promoter fragments fused to a chloramphenicol acetyltransferase reporter gene. Both effector agents caused a marked increase of the transcriptional activity of an LDH -830/+25 bp promoter/CAT construct. In contrast, a phorbol ester which fails to activate protein kinase C, phorbol 12 beta,13 alpha-didecanoate, had no effect on the LDH promoter activity. Transient transfection analysis of LDH promoter deletion/CAT constructs, DNA/protein binding assays, including footprint and gel shift analyses, identified a TRE/AP-1 enhancer module at position -294 bp which was the target for the protein kinase C-mediated signal transduction pathway. Thus, our data demonstrate an active role of the protein kinase C signal pathway in regulating LDH A subunit gene expression which may be significant in regulating LDH isozyme patterns under various physiologic conditions.
Huang
D
D
Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, IL 60611, USA.
Jungmann
R A
RA
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D004075:Diglycerides / Q000494:pharmacology; D005809:Genes, Regulator; D005910:Glioma / Q000737:chemistry / Q000201:enzymology / Q000473:pathology; D007211:Indoles / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000235:genetics*; D008301:Maleimides / Q000494:pharmacology; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured
D004075:Diglycerides; D007211:Indoles; D008301:Maleimides; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; C044295:1,2-dioctanoylglycerol; D004247:DNA; D007770:L-Lactate Dehydrogenase; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate