Related Experiment Video
Updated: Jul 16, 2026
Lineage Tracing and Clonal Analysis in Developing Cerebral Cortex Using Mosaic Analysis with Double Markers (MADM)
Published on: May 8, 2020
Modeling sporadic loss of heterozygosity in mice by using mosaic analysis with double markers (MADM)
Mandar Deepak Muzumdar1, Liqun Luo, Hui Zong
1Howard Hughes Medical Institute and Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
Abstract:
The initiation and progression of many human cancers involve either somatic activation of protooncogenes or inactivation of tumor-suppressor genes (TSGs) in sporadic cells. Although sporadic gain-of-function of protooncogenes has been successfully modeled in mice [e.g., Johnson L, Mercer K, Greenbaum D, Bronson RT, Crowley D, Tuveson DA, Jacks T (2001) Nature 410:1111-1116], generating a similar degree of sparseness of TSG loss-of-function remains a challenge. Here, we use mosaic analysis with double markers (MADM) to achieve TSG inactivation and concurrent labeling in sporadic somatic cells of mice, closely mimicking loss of heterozygosity as occurs in human cancers. As proof of principle, we studied the consequence of sporadic loss of p27kip1, a cyclin-dependent kinase inhibitor. MADM-mediated loss of p27kip1 results in mutant cell expansion markedly greater than that observed in conventional p27kip1 knockouts. Moreover, the direct comparison of WT and mutant cells at single-cell resolution afforded by MADM reveals that p27kip1 regulates organ size in vivo by cell-autonomous control of cell cycle exit timing. These studies establish MADM as a high-resolution method for modeling sporadic loss of heterozygosity in mice, providing insights into TSG function.
Insights
Mosaic analysis with double markers (MADM) enables modeling of sporadic tumor-suppressor gene (TSG) loss in mice, revealing p27kip1
Area of Science:
- Cancer Biology
- Genetics
- Developmental Biology
Background:
- Cancer initiation involves protooncogene activation or tumor-suppressor gene (TSG) inactivation in sporadic cells.
- Modeling sporadic TSG loss-of-function in mice is challenging.
- Mosaic analysis with double markers (MADM) offers a solution for studying TSG inactivation.
Purpose of the Study:
- To establish MADM as a method for modeling sporadic TSG loss-of-function in mice.
- To investigate the role of p27kip1 in cancer development and organ size regulation.
- To provide insights into TSG function using a high-resolution technique.
Main Methods:
- Utilized mosaic analysis with double markers (MADM) in mice.
- Achieved concurrent TSG inactivation and cell labeling in sporadic somatic cells.
- Studied the consequences of sporadic p27kip1 loss.
Main Results:
- MADM successfully modeled sporadic TSG inactivation, mimicking loss of heterozygosity in human cancers.
- MADM-mediated loss of p27kip1 led to greater mutant cell expansion than conventional knockouts.
- p27kip1 was found to regulate organ size via cell-autonomous control of cell cycle exit timing.
Conclusions:
- MADM is a high-resolution method for modeling sporadic loss of heterozygosity in mice.
- This technique provides valuable insights into TSG function.
- p27kip1 plays a critical role in controlling organ size through cell cycle regulation.
