Sleeping beauty-mediated somatic mutagenesis implicates CSF1 in the formation of high-grade astrocytomas
Aaron M Bender1, Lara S Collier, Fausto J Rodriguez
1Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Abstract:
The Sleeping Beauty (SB) transposon system has been used as an insertional mutagenesis tool to identify novel cancer genes. To identify glioma-associated genes, we evaluated tumor formation in the brain tissue from 117 transgenic mice that had undergone constitutive SB-mediated transposition. Upon analysis, 21 samples (18%) contained neoplastic tissue with features of high-grade astrocytomas. These tumors expressed glial markers and were histologically similar to human glioma. Genomic DNA from SB-induced astrocytoma tissue was extracted and transposon insertion sites were identified. Insertions in the growth factor gene Csf1 were found in 13 of the 21 tumors (62%), clustered in introns 5 and 8. Using reverse transcription-PCR, we documented increased Csf1 RNAs in tumor versus adjacent normal tissue, with the identification of transposon-terminated Csf1 mRNAs in astrocytomas with SB insertions in intron 8. Analysis of human glioblastomas revealed increased levels of Csf1 RNA and protein. Together, these results indicate that SB-insertional mutagenesis can identify high-grade astrocytoma-associated genes and they imply an important role for CSF1 in the development of these tumors.
Insights
The Sleeping Beauty (SB) transposon system identified the growth factor gene Csf1 as a potential driver of high-grade astrocytomas. This finding highlights CSF1
Area of Science:
- Genetics
- Oncology
- Neuroscience
Background:
- The Sleeping Beauty (SB) transposon system is a powerful tool for insertional mutagenesis.
- Identifying genes driving glioma development is crucial for understanding and treating brain tumors.
Purpose of the Study:
- To identify novel genes associated with glioma development using SB-mediated transposition.
- To investigate the role of identified genes in high-grade astrocytoma formation.
Main Methods:
- Utilized SB-mediated transposition in 117 transgenic mice to induce tumor formation.
- Analyzed tumor tissue for neoplastic changes and characterized transposon insertion sites.
- Employed reverse transcription-PCR to quantify Csf1 RNA levels in tumor and normal tissues.
Main Results:
- 18% of mice developed high-grade astrocytomas similar to human glioma.
- Insertions in the Csf1 gene were found in 62% of tumors, specifically in introns 5 and 8.
- Elevated Csf1 RNA and protein levels were observed in both mouse and human glioblastomas.
Conclusions:
- SB-insertional mutagenesis is effective in identifying high-grade astrocytoma-associated genes.
- The growth factor gene Csf1 plays a significant role in the development of these brain tumors.
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