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Updated: Sep 29, 2026
Retroviral Scanning: Mapping MLV Integration Sites to Define Cell-specific Regulatory Regions
Published on: May 28, 2017
Large-scale identification of novel potential disease loci in mouse leukemia applying an improved strategy for
Marieke Joosten1, Yolanda Vankan-Berkhoudt, Marjolein Tas
1The Institute of Hematology, Erasmus University Rotterdam, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands.
Abstract:
The identification of common virus integration sites (cVIS) in retrovirally induced tumors in mice provides a powerful strategy to isolate novel transforming genes. Applying virus LTR-specific inverse-PCR and RT-PCR combined with automated sequencing on CasBr-M Murine Leukemia Virus (MuLV) induced myeloid leukemias, 126 virus integration sites were cloned. Using locus- and LTR-specific primers, a nested-PCR/Southern-blotting procedure was developed on genomic DNA from a large panel of MuLV-induced leukemias, to analyse whether a particular virus insertion represented a cVIS. In fact 39 out of 41 integrations analysed this way appeared to represent a common virus integration. We recognized six previously cloned cVISs, i.e. Evi1, Hoxa7, c-Myb, Cb2/Evi11, Evi12, and His1 and 33 novel common insertions, designated Cas-Br Virus Integration Site (Casvis). Among this group we found integrations in or near genes encoding nuclear proteins, e.g. Dnmt-2, Nm23-M2, Ctbp1 or Erg, within receptor genes, e.g. Cb2 or mrc1, novel putative signaling or transporter genes, the ringfinger-protein gene Mid1 and a panel of genes encoding novel proteins with unknown function. The finding that 39 out of 41 integrations analysed represented a cVIS, suggests that the majority of the other virus insertions that were not yet analysed by the PCR/Southern-blotting method are located in a cVIS as well and may therefore also harbor novel disease genes.
Insights
Identifying common virus integration sites (cVIS) in mouse tumors helps find new transforming genes. This study found 33 novel cVIS in myeloid leukemias, suggesting many viral insertions harbor disease-causing genes.
Area of Science:
- * Molecular Biology
- * Oncology
- * Virology
Background:
- * Retroviral insertions in mouse tumors are a known method for identifying oncogenes.
- * Common virus integration sites (cVIS) are crucial for understanding insertional mutagenesis.
Purpose of the Study:
- * To identify novel common virus integration sites (cVIS) in CasBr-M Murine Leukemia Virus (MuLV)-induced myeloid leukemias.
- * To characterize genes located at these novel integration sites.
Main Methods:
- * Virus LTR-specific inverse-PCR and RT-PCR with automated sequencing.
- * Nested-PCR/Southern-blotting on genomic DNA from MuLV-induced leukemias.
- * Analysis of virus integration sites in a large panel of tumors.
Main Results:
- * 126 virus integration sites were cloned from CasBr-M MuLV-induced myeloid leukemias.
- * 39 out of 41 analyzed integrations were confirmed as cVIS.
- * Six previously known cVIS and 33 novel cVIS (Casvis) were identified, including integrations near genes involved in nuclear functions, signaling, and transport.
Conclusions:
- * The majority of viral insertions in MuLV-induced leukemias occur at cVIS.
- * Novel disease genes are likely located at these newly identified Casvis sites.
- * This strategy effectively identifies potential oncogenes and disease-related genes.
