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W Nordstrom

Publications and source records attributed to W Nordstrom.

5 recordsLinked to original sources

Drosophila p53 binds a damage response element at the reaper locus.

The tumor suppressor gene p53 regulates multiple cellular responses to DNA damage, but the transcriptional targets that specify these responses are incompletely understood. We describe a Drosophila p53 homolog and demonstrate that it can activate transcription from a promoter containing binding sites for human p53. Dominant-negative forms of Drosophila p53 inhibit both transactivation in cultured cells and radiation-induced apoptosis in developing tissues. The cis-regulatory region of the proapoptotic gene reaper contains a radiation-inducible enhancer that includes a consensus p53 binding site. Drosophila p53 can activate transcription from this site in yeast and a multimer of this site is sufficient for radiation induction in vivo. These results indicate that reaper is a direct transcriptional target of Drosophila p53 following DNA damage.

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Guardian ancestry: fly p53 and damage-inducible apoptosis.

The tumor suppressor, p53, is among the most commonly mutated genes in human cancers. Recent reports describe shared and divergent properties of a Drosophila p53 homolog Dmp53. Like its mammalian counterpart, Dmp53 also functions in damage-induced cell death. In this model system, the apoptosis activator reaper has emerged as an important target gene. Together with the wealth of genomic data available in Drosophila, continued studies on Dmp53 promise new insights into the regulation and function of this important gene family.

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Activation of the reaper gene during ectopic cell killing in Drosophila.

The product of the reaper (rpr) gene is required for programmed cell death in Drosophila. We examined rpr expression during ectopic cell deaths caused by ionizing radiation or aberrant development. In both instances, dramatic induction of rpr expression was observed. A genomic fragment upstream of rpr confers this regulatory behavior upon a lacZ reporter transgene. In a model cell culture system, conditional expression of REAPER is sufficient to induce massive apoptosis that can be prevented by the anti-apoptotic protein p35. Overall, these results suggest that diverse signals converge at, or upstream of, rpr-associated transcriptional regulatory elements that can function to initiate a common apoptotic pathway involving ICE-like protease activity.

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grim, a novel cell death gene in Drosophila.

A genomic interval at 75C1,2 is required for programmed cell death in Drosophila. We identified a new activator of apoptosis, grim, which maps between two previously identified cell death genes in this region reaper (rpr) and head involution defective (hid). Expression of grim RNA coincided with the onset of programmed cell death at all stages of embryonic development, whereas ectopic induction of grim triggered extensive apoptosis in both transgenic animals and in cell culture. Cell killing by grim was blocked by coexpression of p35, a viral product that inactivates ICE-like proteases, and did not require the functions of rpr or hid. The predicted grim protein shares an amino-terminal motif in common with rpr. However, grim was sufficient to elicit apoptosis in at least one context, where rpr was not. The grim gene product might thus function in a parallel circuit of cell death signaling that ultimately activates a common set of downstream apoptotic effectors.

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