The transcription factor p53 has a crucial role in repressing tumour development but cellular processes that are critical in this process remain unclear. A full understanding of the mechanisms of p53 mediated tumour suppression is expected to give a better comprehension of tumorigenesis. This in turn should facilitate the development of improved strategies for the prevention, early detection and even therapy of cancer. One approach to achieve this is to identify novel tumour suppressors and then study their relationship with p53.
Here, we performed an in vivo whole mouse genome sgRNA library screen using Eµ-Myc_Cas9 haematopietic stem/progenitor cells (HSPCs)to identify novel tumour suppressors. The mouse sgRNA library (Koike-Yusa et al. 2014) contains 87,897 individual sgRNAs targeting 19,150 murine protein-coding genes. The sgRNA library transduced Eµ-Myc_Cas9 HSPCs were transplanted into lethally irradiated wild type recipients to reconstitute their haematopietic system, and then aged to wait for development of B cell lymphoma. The sgRNAs targeting mousep53 or human Bim were used as positive or negative controls, respectively.
Excitingly, we were able to identify several genes accelerating Myc driven lymphomagenesis when compared to conventional Eµ-myctransgenic mice. Amongst known targets, we also identified novel tumour suppressor genes, which we are currently validating. In summary, we have established a quick and reliable whole mouse genome in vivo screening platforms allowing for the identification of novel tumour suppressor genes and hence potential drug targets for future therapies.