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Transcriptional and post‐transcriptional regulation of tyrosine hydroxylase gene by protein kinase C.
Author(s) -
Vyas S.,
Faucon Biguet N.,
Mallet J.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb07583.x
Subject(s) - biology , tyrosine hydroxylase , transcriptional regulation , gene , tyrosine 3 monooxygenase , regulation of gene expression , genetics , gene expression , microbiology and biotechnology , enzyme , biochemistry
The role played by protein kinase C (PKC) in TH gene regulation was investigated at transcriptional and post‐transcriptional levels using PC12 cells. The cells were treated with the phorbol ester TPA, which not only activates PKC but also causes down‐regulation. PKC levels were monitored by [3H]PDBU binding assay and by using an anti‐PKC antibody that detected intact PKC (79 kd) as well as its catalytic and regulatory domains. The [3H]PDBU binding to the membrane‐associated PKC increased within 15‐30 min of TPA treatment; thereafter total cellular [3H]PDBU binding decreased to a minimum of 20% of the control at 8 h. The rate of decrease in binding was greater than the decrease in the intensity of the staining of PKC holo enzyme visualized by anti‐PKC antibody. TH mRNA levels, measured over the same time period, rose within 15 min of TPA treatment to peak at 4 h and subsequently declined below control level, paralleling the depletion of PKC. If cells depleted of PKC were reincubated in the normal medium, a recovery in PKC level was seen and, in parallel, TH mRNA levels increased to above control level. Furthermore, if down‐regulation of PKC was prevented by incubating the cells with the protease inhibitor leupeptin, a decrease beyond control level in TH mRNA was not observed. TPA rapidly induced TH gene transcription; a maximal increase of two‐fold was observed at 15 min, but the transcriptional rate then declined although it did not decrease beyond control values after 8 and 24 h of TPA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)