scholarly journals Transcriptional Regulation of HMG-CoA Synthase and HMG-CoA Reductase Genes by Human ACBP

2008 ◽  
Vol 22 (5-6) ◽  
pp. 515-524 ◽  
Author(s):  
Christina Vock ◽  
Frank Döring ◽  
Inke Nitz
Keyword(s):  
Transcriptional Regulation ◽  
Hmg Coa Reductase ◽  
Coa Reductase

scholarly journals Loss of transcriptional activation of three sterol-regulated genes in mutant hamster cells.

1993 ◽  
Vol 13 (9) ◽  
pp. 5175-5185 ◽  
Author(s):  
M J Evans ◽  
J E Metherall
Keyword(s):  
Transcriptional Regulation ◽  
Cell Lines ◽  
Transcriptional Activation ◽  
Cho Cells ◽  
Mutant Cell ◽  
Chinese Hamster ◽  
Wild Type ◽  
Hmg Coa Reductase ◽  
Low Levels ◽  
Coa Reductase

Cholesterol biosynthesis and uptake are controlled by a classic end product-feedback mechanism whereby elevated cellular sterol levels suppress transcription of the genes encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, HMG-CoA reductase, and the low-density lipoprotein receptor. The 5'-flanking region of each gene contains a common cis-acting element, designated the sterol regulatory element (SRE), that is required for transcriptional regulation. In this report, we describe mutant Chinese hamster ovary (CHO) cell lines that lack SRE-dependent transcription. Mutant cell lines were isolated on the basis of their ability to survive treatment with amphotericin B, a polyene antibiotic that kills cells by interacting with cholesterol in the plasma membrane. Four mutant lines (SRD-6A, -B, -C, and -D) were found to be cholesterol auxotrophs and demonstrated constitutively low levels of mRNA for all three sterol-regulated genes even under conditions of sterol deprivation. The mutant cell lines were found to be genetically recessive, and all four lines belonged to the same complementation group. When transfected with a plasmid containing a sterol-regulated promoter fused to a bacterial reporter gene, SRD-6B cells demonstrated constitutively low levels of transcription, in contrast to wild-type CHO cells, which increased transcription under conditions of sterol deprivation. Mutation of the SREs in this plasmid prior to transfection reduced the level of expression in wild-type CHO cells deprived of sterols to the level of expression found in SRD-6B cells. The defect in SRD-6 cells is limited to transcriptional regulation, since posttranscriptional mechanisms of sterol-mediated regulation were intact: the cells retained the ability to posttranscriptionally suppress HMG-CoA reductase activity and to stimulate acyl-CoA:cholesterol acyltransferase activity. These results suggest that SRD-6 cells lack a factor required for SRE-dependent transcriptional activation. We contrast these cells with a previously isolated oxysterol-resistant cell line (SRD-2) that lacks a factor required for SRE-dependent transcriptional suppression and propose a model for the role of these genetically defined factors in sterol-mediated transcriptional regulation.

scholarly journals Loss of transcriptional activation of three sterol-regulated genes in mutant hamster cells

1993 ◽  
Vol 13 (9) ◽  
pp. 5175-5185
Author(s):  
M J Evans ◽  
J E Metherall
Keyword(s):  
Transcriptional Regulation ◽  
Cell Lines ◽  
Transcriptional Activation ◽  
Cho Cells ◽  
Mutant Cell ◽  
Chinese Hamster ◽  
Wild Type ◽  
Hmg Coa Reductase ◽  
Low Levels ◽  
Coa Reductase

Cholesterol biosynthesis and uptake are controlled by a classic end product-feedback mechanism whereby elevated cellular sterol levels suppress transcription of the genes encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, HMG-CoA reductase, and the low-density lipoprotein receptor. The 5'-flanking region of each gene contains a common cis-acting element, designated the sterol regulatory element (SRE), that is required for transcriptional regulation. In this report, we describe mutant Chinese hamster ovary (CHO) cell lines that lack SRE-dependent transcription. Mutant cell lines were isolated on the basis of their ability to survive treatment with amphotericin B, a polyene antibiotic that kills cells by interacting with cholesterol in the plasma membrane. Four mutant lines (SRD-6A, -B, -C, and -D) were found to be cholesterol auxotrophs and demonstrated constitutively low levels of mRNA for all three sterol-regulated genes even under conditions of sterol deprivation. The mutant cell lines were found to be genetically recessive, and all four lines belonged to the same complementation group. When transfected with a plasmid containing a sterol-regulated promoter fused to a bacterial reporter gene, SRD-6B cells demonstrated constitutively low levels of transcription, in contrast to wild-type CHO cells, which increased transcription under conditions of sterol deprivation. Mutation of the SREs in this plasmid prior to transfection reduced the level of expression in wild-type CHO cells deprived of sterols to the level of expression found in SRD-6B cells. The defect in SRD-6 cells is limited to transcriptional regulation, since posttranscriptional mechanisms of sterol-mediated regulation were intact: the cells retained the ability to posttranscriptionally suppress HMG-CoA reductase activity and to stimulate acyl-CoA:cholesterol acyltransferase activity. These results suggest that SRD-6 cells lack a factor required for SRE-dependent transcriptional activation. We contrast these cells with a previously isolated oxysterol-resistant cell line (SRD-2) that lacks a factor required for SRE-dependent transcriptional suppression and propose a model for the role of these genetically defined factors in sterol-mediated transcriptional regulation.

scholarly journals 3′-untranslated sequences mediate post-transcriptional regulation of 3-hydroxy-3-methylglutaryl-CoA reductase mRNA by 25-hydroxycholesterol

1995 ◽  
Vol 307 (1) ◽  
pp. 233-238 ◽  
Author(s):  
J W Choi ◽  
D M Peffley
Keyword(s):  
Protein Synthesis ◽  
Transcriptional Regulation ◽  
Untranslated Region ◽  
Simian Virus 40 ◽  
Beta Globin ◽  
Hmg Coa Reductase ◽  
Reductase Mrna ◽  
Coa Reductase ◽  
Post Transcriptional Regulation ◽  
Rna Levels

In an earlier study [Choi, Lundquist and Peffley (1993) Biochem. J. 296, 859-866], we determined that 25-hydroxycholesterol regulates 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase mRNA through a post-transcriptional mechanism that requires protein synthesis. To investigate whether 3′-untranslated sequences play a role in 25-hydroxycholesterol-mediated post-transcriptional control, we ligated approx. 1400 bp of the 3′-untranslated region of HMG-CoA reductase cDNA to the coding region of human beta-globin DNA. beta-Globin-3′-untranslated reductase fusion constructs were then transiently expressed in Chinese hamster ovary fibroblasts under conditions known to regulate reductase mRNA. There were no differences in beta-globin RNA levels in transfected cells incubated with or without lovastatin, a competitive inhibitor of reductase. However, in the presence of lovastatin and an oxysterol, 25-hydroxycholesterol, beta-globin RNA levels were decreased approx. 2-fold. Inhibition of protein synthesis with cycloheximide blocked the effects of 25-hydroxycholesterol on beta-globin RNA. Moreover, replacing the 3′-untranslated sequences with 1367 bp of the simian virus 40 enhancer region eliminated the regulatory effect of 25-hydroxycholesterol. Because the fusion construct has no sterol regulatory elements necessary for transcription, our results indicate that the change in beta-globin RNA occurred at a post-transcriptional level. In addition, we have shown that the 3′-untranslated region of HMG-CoA reductase cDNA imparted oxysterol-mediated post-transcriptional regulation to beta-globin RNA, an effect that required protein synthesis.

Reduction of HMG-CoA-reductase leads to improved cardiac function in doxorubicin-induced cardiomyopathy in mice

2008 ◽  
Vol 7 ◽  
pp. 202-203
Author(s):  
A RIAD ◽  
S BIEN ◽  
F ESCHER ◽  
D WESTERMANN ◽  
U LANDMESSER ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Hmg Coa Reductase ◽  
Coa Reductase
Sign in / Sign up

Export Citation Format

Share Document