Related Experiment Videos
Identification of oncogenes collaborating with p27Kip1 loss by insertional mutagenesis and high-throughput insertion
Harry C Hwang1, Carla P Martins, Yvon Bronkhorst
1Division of Clinical Research and Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA.
Abstract:
The p27(Kip1) protein is a cyclin-dependent kinase inhibitor that blocks cell division in response to antimitogenic cues. p27 expression is reduced in many human cancers, and p27 functions as a tumor suppressor that exhibits haploinsufficiency in mice. Despite the well characterized role of p27 as a cyclin-dependent kinase inhibitor, its mechanism of tumor suppression is unknown. We used Moloney murine leukemia virus to induce lymphomas in p27+/+ and p27-/- mice and observed that lymphomagenesis was accelerated in the p27-/- animals. To identify candidate oncogenes that collaborate with p27 loss, we used a high-throughput strategy to sequence 277 viral insertion sites derived from two distinct sets of p27-/- lymphomas and determined their chromosomal location by comparison with the Celera and public (Ensembl) mouse genome databases. This analysis identified a remarkable number of putative protooncogenes in these lymphomas, which included loci that were novel as well as those that were overrepresented in p27-/- tumors. We found that Myc activations occurred more frequently in p27-/- lymphomas than in p27+/+ tumors. We also characterized insertions within two novel loci: (i) the Jun dimerization protein 2 gene (Jundp2), and (ii) an X-linked locus termed Xpcl1. Each of the loci that we found to be frequently involved in p27-/- lymphomas represents a candidate oncogene collaborating with p27 loss. This study illustrates the power of high-throughput insertion site analysis in cancer gene discovery.
Insights
Loss of the p27(Kip1) protein accelerates lymphoma development. High-throughput sequencing identified novel oncogenes, including Jundp2 and Xpcl1, that collaborate with p27 loss in cancer.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- p27(Kip1) is a cyclin-dependent kinase inhibitor crucial for blocking cell division.
- Reduced p27 expression is common in human cancers, and it acts as a tumor suppressor.
- The precise mechanism of p27's tumor suppression function remains largely unknown.
Purpose of the Study:
- To investigate the role of p27 loss in lymphomagenesis.
- To identify oncogenes that cooperate with p27 loss in cancer development.
- To understand the molecular mechanisms underlying p27-mediated tumor suppression.
Main Methods:
- Lymphomas were induced in p27+/+ and p27-/- mice using Moloney murine leukemia virus.
- High-throughput sequencing was employed to analyze 277 viral insertion sites in p27-/- lymphomas.
- Viral insertion sites were mapped to the mouse genome using Celera and Ensembl databases.
Main Results:
- Lymphomagenesis was significantly accelerated in p27-/- mice compared to p27+/+ controls.
- Analysis revealed numerous putative protooncogenes, including novel and overrepresented loci in p27-/- tumors.
- Frequent Myc activations were observed in p27-/- lymphomas. Insertions in Jun dimerization protein 2 (Jundp2) and Xpcl1 were identified as novel candidate oncogenes.
Conclusions:
- The loss of p27(Kip1) collaborates with oncogene activation to promote lymphomagenesis.
- Jundp2 and Xpcl1 represent novel candidate oncogenes that cooperate with p27 loss.
- High-throughput insertion site analysis is a powerful tool for discovering cancer-associated genes.