Epigenetic of Vector-Chromatin Interactions

• Applicant: Dr. Manuel Grez
• Subject Area: Hematology, Oncology
• Term: from 2006 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 22792556

Integration of MLV-derived vectors occurs mainly in a 30 kb window around the transcription initiation site of targeted genes. The analysis of retroviral integration sites in samples from two X-CGD patients treated with gene transduced cells, revealed an unprecedented clustering of retroviral integrations in two genes (MDS/EVI1 and PRDM16) at almost identical sites in both patients. Similar integration patterns have been observed in samples from non-human primates and mice repopulated with gene transduced cells and in vitro after retroviral transduction of murine hematopoietic stem cells and prolonged culturing. Although the finding of retroviral integration into the MDS/EVi1 and PRDM 16 genes likely reflects selection of clones containing integrations at these sites, the clustering of integrations within a narrow window of less than 4 kb (> 60% of integrations into the PRDM16 gene occurs in a region of less than 3 kb!) can not be explained solely by clonal selection, since transactivation by viral LTRs has been observed over long distances. Therefore other features, like topological constrains including the presence of DNaseI hypersensitive sites or S/MARS elements at these integration sites, may account for these findings. The aim of this proposal is to investigate the molecular basis of this observation. This study will provide new insight into the molecular mechanisms underlying retrovirus ¿ chromatin interactions and will define the cellular and molecular events associated with preferential retroviral integration at cluster sites.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1230: Mechanisms of Gene Vector Entry and Persistence