Drosophila p53 binds a damage response element at the reaper locus

Area of Science:

• Molecular Biology
• Genetics
• Developmental Biology

Background:

• The tumor suppressor p53 is crucial for cellular responses to DNA damage, but its transcriptional targets remain largely unknown.
• Understanding p53's regulatory network is essential for deciphering DNA damage response pathways.

Purpose of the Study:

• To identify and characterize a Drosophila p53 homolog.
• To investigate the role of Drosophila p53 in transcriptional regulation and apoptosis following DNA damage.
• To determine if the proapoptotic gene reaper is a direct transcriptional target of Drosophila p53.

Main Methods:

• Cloning and characterization of a Drosophila p53 homolog.
• Assays for transcriptional activation using p53 binding sites in yeast and cultured cells.
• Functional analysis of dominant-negative p53 forms in vivo.
• Identification and analysis of the cis-regulatory region of the reaper gene.
• In vivo studies of radiation-induced gene expression.

Main Results:

• A functional Drosophila p53 homolog was identified, capable of activating transcription from human p53 binding sites.
• Dominant-negative Drosophila p53 inhibited transactivation and radiation-induced apoptosis.
• The proapoptotic gene reaper possesses a radiation-inducible enhancer with a p53 binding site.
• Drosophila p53 directly activated transcription from the reaper enhancer in yeast and in vivo.

Conclusions:

• Drosophila p53 acts as a transcriptional regulator in response to DNA damage.
• The reaper gene is a direct transcriptional target of Drosophila p53.
• This study elucidates a key component of the DNA damage response pathway in Drosophila, conserved with mammals.