Identification of a p53-dependent negative response element in the Bcl-2 gene

La Jolla Cancer Research Foundation, Cancer Research Center, California 92037.
Cancer Research (Impact Factor: 9.28). 07/1994; 54(12):3131-5.
Source: PubMed

ABSTRACT Recently, we have shown that the p53 tumor suppressor gene product can inhibit expression of the bcl-2 gene. In this report, we explored the molecular basis for p53-mediated down-regulation of bcl-2 gene expression using a cotransfection approach involving p53 expression plasmids and chloramphenicol acetyltransferase (CAT) reporter gene constructs containing regions from the bcl-2 gene. When transfected into a p53-deficient human lung cancer cell line H358, reporter gene constructs containing only the promoter region of bcl-2 and upstream sequences were not suppressed by p53. Inclusion of bcl-2 gene sequences corresponding to the 5' untranslated region in bcl-2/CAT constructs, however, resulted in p53-dependent down-regulation. A 195-base pair segment from the bcl-2 gene 5' untranslated region was found to be capable of conferring p53-dependent repression on a heterologous expression plasmid containing CAT under the control of an SV40 immediate early-region promoter. This p53-negative response element functioned in an orientation-independent manner when placed either upstream or downstream of the SV40-CAT transcription unit. The results demonstrate the existence of a negative response element in the bcl-2 gene through which p53 may either directly or indirectly transcriptionally down-regulate expression of this gene involved in the regulation of programmed cell death.

  • Source
    • "These results suggest that the anterior hindbrain truncation in gbx2 morphants may arise from a combination of decreased proliferation and increased cell death. It has been shown that non-specific cell death caused by morpholinos can be due to an upregulation of p53, which modulates a variety of pro-apoptotic genes (Miyashita et al., 1994; Roperch et al., 1998; Robu et al., 2007). To test whether the cell death in r2, r3, and r5 is specific to gbx2 knockdown, we co-injected embryos with p53-MO to minimize non-specific apoptosis. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The amino acid sequence across the DNA-binding homeodomain of Gbx2 is highly conserved across multiple species. In mice, Gbx2 is essential for establishment of the midbrain-hindbrain boundary (MHB), and in development of anterior hindbrain structures, rhombomeres (r) 1-r3, and the r2/r3-derived cranial nerve V. In contrast, studies in zebrafish have implicated gbx1 in establishment of the MHB. Therefore, we tested potential roles for gbx2 in anterior hindbrain development in zebrafish. gbx2 knockdown with antisense morpholino results in increased cell death in r2, r3, and r5 and a truncation of the anterior hindbrain, similar to the defect in Gbx2(-/-) mice. Moreover, there is abnormal clustering of cranial nerve V cell bodies in r2 and r3 indicative of defects in aspects of anterior hindbrain patterning. These phenotypes can be rescued by expression of the mouse GBX2 protein. These results suggest that gbx2/Gbx2 has an evolutionarily conserved role in anterior hindbrain development.
    Developmental Dynamics 04/2011; 240(4):828-38. DOI:10.1002/dvdy.22589 · 2.67 Impact Factor
  • Source
    • "On the other hand, B has elicited an enhanced expression of p53 mRNA and protein content and it has also enhanced the p53 nuclear localization. In this sub-cellular compartment p53 acts as a factor involved in transcriptional regulation of two well known p53 target genes with opposite functions like Bcl-2 and PTEN [18] [19]. Fig. 2. Bergapten up-regulates the expression of p53, p21, p-Bcl2 while PUVA induces apoptotic events. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study we have reported that bergapten (B) and bergapten plus UV (PUVA) are able to significantly affect MCF-7, ZR-75 and SKBR-3 breast cancer cell proliferations. B induced a lowering of PI3K/AKT survival signal in MCF-7 cells even in presence of IGF-I stimulation. Furthermore, B and in a higher extent, PUVA up-regulated the p53 mRNA and the protein content. An increased co-association between p21 WAF and proliferating cell nuclear antigen (PCNA) has been observed in PUVA-treated MCF-7 cells, thus inhibiting DNA replication. These results highlight how B, and its photoactivated compound, exert antiproliferative effects and induce apoptotic responses in breast cancer cells.
    FEBS letters 04/2010; 584(11):2321-6. DOI:10.1016/j.febslet.2010.04.001 · 3.34 Impact Factor
  • Source
    • "In contrast, Bcl-2 is one of the key genes known to downregulate BAX and certain tumour suppressor proteins , and therefore has the potency to inhibit the intrinsic mitochondrial pathway of apoptosis (Hockenbery 1992; Miyashita et al. 1994). Previous studies have demonstrated that a decreased expression of Bcl-2 is associated with LEC apoptosis and Fig. 5. Bcl-2 mRNA expression of untreated Lens epithelial cells after illumination with plain white light (black columns) and after preincubation with coQ10 (grey columns), as investigated by quantitative RT-PCR. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cataract is one of the most prevalent eye disease and a major cause for legal blindness in the world. Beside others, cumulative light-exposure and apoptotic cell death are significantly associated with cataract development. In contrast, supplementation with antioxidants has been suggested to prevent premature cataractogenesis. This study investigates possible protective effects of Coenzyme Q10 (CoQ10) regarding light-induced stress and apoptotic cell death in human lens epithelial cells (LEC). Human LEC were either pre-incubated with CoQ10 or not and then exposed to white light. After 10-40 min of irradiation viability, induction of intracellular reactive oxygen species (ROS), apoptosis and cell death was determined. Expression of apoptotic BAX and anti-apoptotic Bcl-2 protein and their mRNA were determined by RT-PCR and Western blot analysis. Light exposure decreased LEC viability and Bcl-2 expression and increased intracellular ROS, apoptotic cell death, and BAX expression in a time-of-irradiation-dependent manner. Phototoxic cell death and apoptosis, as well as decrease of Bcl-2 and increase in BAX expression was significantly reduced, when cells were pre-incubated with CoQ10. In this study, CoQ10 significantly reduced light-induced LEC-damage and attenuated phototoxic effects on BAX and Bcl-2 expression. Therefore, CoQ10 supplementation might also be useful in preventing LEC death and consecutive cataract formation in vivo.
    Acta ophthalmologica 04/2010; 88(3):e78-86. DOI:10.1111/j.1755-3768.2010.01875.x · 2.51 Impact Factor
Show more


Available from