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A Detailed Protocol for Characterizing the Murine C1498 Cell Line and its Associated Leukemia Mouse Model
Published on: October 14, 2016
Discovery of novel murine PML isoforms
Karolína Anderová1, Lenka Horníková1, Vojtěch Šroller1
1Department of Genetics and Microbiology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic.
Abstract:
Promyelocytic leukemia protein (PML) orchestrates the formation of PML nuclear bodies (PML NBs), membraneless organelles with diverse regulatory roles. Despite their importance, the specific functions of individual PML splicing variants remain unclear, particularly in murine models. Here we study the repertoire of murine PML isoforms expressed in mouse tissues and cells. We demonstrate that in addition to canonical mPML1-3, mice express five predicted variants (mPMLX1, mPMLX2, mPMLX4-X6) and a novel isoform, mPMLX7, distinguished by unique RBCC domain splicing. All isoforms exhibit distinct turnover kinetics at endogenous PML NBs. In PML-knockout cells, all isoforms except mPMLX7 form NBs de novo and are degraded upon arsenic exposure. Molecular dynamics simulations suggest mPMLX7 adopts a stable conformation; furthermore, this isoform is enriched in the nucleoplasm, suggesting a specialized function. Altogether, this isoform-resolved PML system provides a relevant model for dissecting the wide spectrum of PML-associated processes.
Insights
Researchers characterized mouse Promyelocytic leukemia protein (PML) isoforms, revealing distinct functions and turnover rates. A novel isoform, mPMLX7, shows unique properties, suggesting specialized roles in nuclear bodies and nucleoplasm.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Promyelocytic leukemia protein (PML) is crucial for forming PML nuclear bodies (PML NBs), which are vital membraneless organelles.
- The specific roles of individual PML splicing variants are not well understood, especially in mouse models.
- Understanding PML isoform function is key to deciphering PML NB biology and associated cellular processes.
Purpose of the Study:
- To investigate the repertoire of murine PML isoforms expressed in mouse tissues and cells.
- To characterize the distinct properties and functions of different PML isoforms, including turnover kinetics and localization.
- To establish an isoform-resolved PML system for studying PML NB-associated processes.
Main Methods:
- Analysis of murine PML isoform expression in various mouse tissues and cells.
- Characterization of isoform-specific turnover kinetics at endogenous PML NBs.
- Assessment of de novo PML NB formation and degradation in PML-knockout cells upon arsenic exposure.
- Molecular dynamics simulations to predict isoform conformation and stability.
- Subcellular localization studies to determine enrichment in nucleoplasm or PML NBs.
Main Results:
- Identified canonical mPML1-3 and five predicted variants (mPMLX1, mPMLX2, mPMLX4-X6), plus a novel isoform, mPMLX7, with unique RBCC domain splicing.
- All identified PML isoforms exhibit distinct turnover rates within endogenous PML NBs.
- Except for mPMLX7, all isoforms can form PML NBs de novo in PML-knockout cells and are degraded by arsenic.
- Molecular dynamics simulations indicate mPMLX7 possesses a stable conformation and is enriched in the nucleoplasm, suggesting a specialized function.
Conclusions:
- The study comprehensively characterizes murine PML isoforms, revealing significant diversity in their expression, localization, and dynamics.
- The novel mPMLX7 isoform displays unique characteristics, including nucleoplasmic enrichment and resistance to de novo NB formation/degradation, pointing to specialized functions.
- This isoform-resolved PML system provides a valuable model for future research into the multifaceted roles of PML and PML NBs in cellular regulation.
