Transcriptional regulation of apolipoprotein E expression by cyclic AMP

FEBS Letters

Andreani-Mangeney, Marise¹  Bereziat, Gilbert¹  Girlich, Delphine¹  Janvier, Brigitte¹  Vandenbrouck, Yves¹ 

[1] CNRS URA 1283, CHU Saint Antoine, 27 rue Chaligny, 75012 Paris, France

关键词: Apolipoprotein E;    Gene expression;    Cyclic AMP;    ApoE;    apolipoprotein E;    cAMP;    cyclic AMP;    CAT;    chloramphenicol acetyltransferase;    CRE;    cAMP-responsive element;    CREB;    CRE-binding protein;    db-cAMP;    dibutyryl cyclic AMP;    PKA;    protein kinase A;    SPAP;    secreted placental alkaline phosphatase;    ICER;    inducible cAMP early repressor;   

DOI  :  10.1016/S0014-5793(96)01168-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Incubation of HepG2 cells in the presence of dibutyryl cAMP (db-cAMP), a cell permeable analogue of cyclic AMP, or forskolin, an agent which elevates intracellular cAMP, resulted in a 50% decrease in apoE mRNA levels within 24 h. Results of nuclear run-on transcription assays showed that db-cAMP down-regulates apoE gene expression at the transcriptional level. By transfection analysis with a plasmid containing the human apoE gene fused to the secreted placental alkaline phosphatase (SPAP) reporter gene, we showed that the SPAP activity was decreased by 50% when HepG2 cells were incubated in the presence of db-cAMP or forskolin, indicating that this promoter region mediated this negative effect. In contrast, when the smaller fragment of apoE promoter was linked to the CAT reporter gene, db-cAMP treatment of HepG2 cells resulted in a 2-fold increase in CAT activity, suggesting that positive cAMP-responsive elements were present in the proximal apoE promoter. These data indicate that transcriptional modulation of apoE gene expression by agents known to elevate the intracellular cAMP level is complex and involves several negative and positive elements located in the −614 to +804 region of the apoE gene whose global effect is negative on apoE gene transcription.

【 授权许可】

Unknown