title: microRNAs and Alu elements in the p53-Mdm2-Mdm4 regulatory network.
abstract: p53 is a transcription factor that governs numerous stress response pathways within the cell. Maintaining the right levels of p53 is crucial for cell survival and proper cellular homeostasis. The tight regulation of p53 involves many cellular components, most notably its major negative regulators Mdm2 and Mdm4, which maintain p53 protein amount and activity in tight check. microRNAs (miRNAs) are small non-coding RNAs that target specific mRNAs to translational arrest and degradation. miRNAs are also key components of the normal p53 pathway, joining forces with Mdm2 and Mdm4 to maintain proper p53 activity. Here we review the current knowledge of miRNAs targeting Mdm2 and Mdm4, and their importance in different tissues and in pathological states such as cancer. In addition, we address the role of Alu sequences-highly abundant retroelements spread throughout the human genome, and their impact on gene regulation via the miRNA machinery. Alus occupy a significant portion of genes' 3'UTR, and as such they have the potential to impact mRNA regulation. Since Alus are primate-specific, they introduce a new regulatory layer into primate genomes. Alus can influence and alter gene regulation, creating primate-specific cancer-preventive regulatory mechanisms to sustain the transition to longer life span in primates. We review the possible influence of Alu sequences on miRNA functionality in general and specifically within the p53 network.
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Yonit
authors.initials: Y
authors.lastname: Hoffman
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel pilpel@weizmann.ac.il moshe.oren@weizmann.ac.il.
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Pilpel
authors.affiliation: Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel pilpel@weizmann.ac.il moshe.oren@weizmann.ac.il.
authors.forename: Moshe
authors.initials: M
authors.lastname: Oren
mesh_terms: D020087:Alu Elements / Q000235:genetics*; D000818:Animals; D053263:Gene Regulatory Networks; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; D009687:Nuclear Proteins; D016159:Tumor Suppressor Protein p53; D051736:Proto-Oncogene Proteins c-mdm2
keywords: Alu; Mdm2; Mdm4; microRNA; p53