A cross–nearest neighbor/Monte Carlo algorithm for single-molecule localization microscopy defines interactions between p53, Mdm2, and MEG3

Abstract

<jats:title>Abstract</jats:title><jats:p>The functions of long noncoding (lnc)RNAs such as MEG3 are defined by their interactions with other RNAs and proteins. These interactions, in turn, are shaped by their subcellular localization and temporal context. Therefore, it is important to be able to analyze the relationships of lncRNAs while preserving cellular architecture. The ability of MEG3 to suppress cell proliferation led to its recognition as a tumor suppressor. MEG3 has been proposed to activate p53 by disrupting the interaction of p53 with Mdm2. To test this mechanism in the native cellular context, we employed two-color direct stochastic optical reconstruction microscopy (dSTORM), a single-molecule localization microscopy (SMLM) technique to detect and quantify the localizations of p53, Mdm2, and MEG3 in U2OS cells. We developed a new cross–nearest neighbor/Monte Carlo algorithm to quantify the association of these molecules. Proof of concept for our method was obtained by examining the binding between MEG3 and p53, and Mdm2 and p53. In contrast to previous models, our data support a model in which MEG3 modulates p53 independently of the interaction with Mdm2.</jats:p>

Hirudin Suppresses Metastasis of Human Breast Adenocarcinoma Cells In Vitro and in a Zebrafish Xenograft Model

“…p53 coordinates a transcription program to stall the cell cycle, promote DNA repair, and initiate senescence or apoptosis. The primary modulators of p53 activity is the E3 ubiquitin-protein ligase MDM2 which constitutively polyubiquitinate p53 for proteasomal degradation, maintaining p53 at low levels [16] . Our result suggests that down-regulation of CHD1L, MDM2 and up-regulation of p53 might be responsible for the anti-metastasis mechanisms of hirudin in breast cancer.…”