[
International Worm Meeting,
2009]
Methods for manipulating gene expression at the experimentalist''s discretion would provide a useful means to analyze diverse biological processes. Heat shock promoters drive the expression of downstream genes in response to heat stimuli. Previous studies showed that irradiation with the visible laser light (440 nm) can induced heat shock response-mediated expression of transgene in targeted cells. However, irradiation with a 440 nm laser, which was originally used for cell ablation, may have detrimental effects on cells. We have developed a novel microscope system called infrared laser-evoked gene operator (IR-LEGO)(Kamei et al., Nat Methods 2009 Jan;6(1):79-81.). Because the absorption coefficient of water is higher in the infrared (IR) region, the IR light would heat cells more efficiently than the visible light. Application of IR-LEGO to C. elegans revealed that irradiation for 1s was sufficient for gene induction in a targeted single seam cell. Under appropriate conditions, 40% of irradiated seam cells expressed GFP under the control of a heat shock promoter, and all irradiated cells developed normally, indicating that the IR irradiation did not cause cell damage. We also found that the expression of MAB-5 and MIG-24 protein induced with IR-LEGO each rescued the phenotypes of the corresponding mutants. We also report on current attempts to induce gene expression in targeted cells of early embryos and in single neurons of the nerve ring.