Down-regulation of expression of a pupal cuticle protein gene by transcriptional and posttranscriptional control mechanisms during metamorphosis in Galleria

We have analyzed the expression of the Dictyostelium gene P8A7 which had been isolated as a cDNA clone from an early developmentally regulated gene. The single genomic copy generated two mRNAs which were subject to different control mechanisms: while one mRNA (P8A7S) was regulated like the cell-type-nonspecific late genes, the other one (P8A7L) was induced during development, when cells were allowed to attach to a substrate, and when cells were subjected to stress, such as heat shock and cadmium. Interestingly the same induction was also observed with cold shock. RNA processing was inhibited by heat and cold shock, leading to nuclear accumulation of a precursor. The translated region of the cDNA was common to both mRNAs and encoded an unusually hydrophobic peptide with the characteristics of a membrane protein.

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A developmentally regulated membrane protein gene in Dictyostelium discoideum is also induced by heat shock and cold shock.

Molecular and Cellular Biology ◽

10.1128/mcb.8.1.153 ◽

1988 ◽

Vol 8 (1) ◽

pp. 153-159 ◽

Cited By ~ 38

Author(s):

M Maniak ◽

W Nellen

Keyword(s):

Heat Shock ◽

Membrane Protein ◽

Rna Processing ◽

Cold Shock ◽

Protein Gene ◽

Nuclear Accumulation ◽

Control Mechanisms ◽

Developmentally Regulated ◽

Hydrophobic Peptide ◽

Membrane Protein Gene

We have analyzed the expression of the Dictyostelium gene P8A7 which had been isolated as a cDNA clone from an early developmentally regulated gene. The single genomic copy generated two mRNAs which were subject to different control mechanisms: while one mRNA (P8A7S) was regulated like the cell-type-nonspecific late genes, the other one (P8A7L) was induced during development, when cells were allowed to attach to a substrate, and when cells were subjected to stress, such as heat shock and cadmium. Interestingly the same induction was also observed with cold shock. RNA processing was inhibited by heat and cold shock, leading to nuclear accumulation of a precursor. The translated region of the cDNA was common to both mRNAs and encoded an unusually hydrophobic peptide with the characteristics of a membrane protein.

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Nitric oxide stimulates cellular degradation of human CYP51A1, the highly conserved lanosterol 14α-demethylase

Biochemical Journal ◽

10.1042/bcj20170459 ◽

2017 ◽

Vol 474 (19) ◽

pp. 3241-3252 ◽

Cited By ~ 8

Author(s):

Ji Won Park ◽

Aria Byrd ◽

Choon-myung Lee ◽

Edward T. Morgan

Keyword(s):

Nitric Oxide ◽

Proteasome Inhibitors ◽

No Synthase ◽

Cytochrome P450 Enzymes ◽

Human Hepatoma Cells ◽

Down Regulation ◽

Regulation Of Expression ◽

No Donors ◽

Huh7 Cells ◽

Ubiquitin Proteasome

Nitric oxide (NO) is known to down-regulate drug-metabolizing cytochrome P450 enzymes in an enzyme-selective manner. Ubiquitin–proteasome-dependent and -independent pathways have been reported. Here, we studied the regulation of expression of human CYP51A1, the lanosterol 14α-demethylase required for synthesis of cholesterol and other sterols in mammals, which is found in every kingdom of life. In Huh7 human hepatoma cells, treatment with NO donors caused rapid post-translational down-regulation of CYP51A1 protein. Human NO synthase (NOS)-dependent down-regulation was also observed in cultured human hepatocytes treated with a cytokine mixture and in Huh7 cells expressing human NOS2 under control of a doxycycline-regulated promoter. This down-regulation was partially attenuated by proteasome inhibitors, but only trace levels of ubiquitination could be found. Further studies with inhibitors of other proteolytic pathways suggest a possible role for calpains, especially when the proteasome is inhibited. NO donors also down-regulated CYP51A1 mRNA in Huh7 cells, but to a lesser degree, than the down-regulation of the protein.

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