Aviso and Oxford University have begun a whole genome screening project using RNAI libraries.
Robotics manufacturer Aviso supplied Dr Neil Brockdorff's lab with the Cellcelector, which can image, analyse and pick mammalian clones from tissue culture dishes.
The Cellcelector allows selection of colonies of interest based on quantitative measurement of fluorescence intensity, an approach not achievable using manual techniques.
Dr Brockdroff, from the Department of Biochemistry at Oxford, said: 'The project will employ a strategy in which pools of short hairpin RNA (shRNAs) directed at all known genes are introduced by viral transduction into cells then subjected to appropriate selection regimes to identify genes of interest.
'Embryonic stem (ES) cells are particularly suited for this approach as they grow as colonies and can be plated at low density such that individual colonies each arise from a single cell expressing a single shRNA directed against a specific gene.
'Carefully tailored reporter ES cell lines can be developed by genetically modifying the locus of interest using well established homologous recombination technologies.
'A simple example is the knock-in strategy in which a reporter, for example a fluorescent protein, is inserted under the control of the promoter of an endogenous locus of interest.
'Following shRNA transduction cells can then be selected based on expression of high or low levels of the marker.' The semi-automated Cellcelector device will be able to analyse batches of plates and quantify, prior to harvesting, which transfectants have responded significantly to RNA interference.
Brockdorff added: 'Specific populations of categorised colonies can be gated and picked from a total of approximately 20,000 colonies.
'To further extend the capabilities of the Cellcelector for pooled shRNA screening in ES cells we are developing screening strategies using reporter cell lines with two or more fluorescent marker proteins.
'Fluorescent intensities for the different marker proteins can then be used to define individual colonies with more specific properties, for example expressing high levels of both fluorescent markers.
'While current efforts are focused on using ES cells, it will also be possible to carry out pooled shRNA screens in other cell types and to use the Aviso Cellcelector to quantitatively select cells/colonies of interest.'
