TARGETED SINGLE-CELL INDUCTION OF GENE-PRODUCTS IN CAENORHABDITIS-ELEGANS - A NEW TOOL FOR DEVELOPMENTAL STUDIES

Heat shock promoters have been employed to achieve tightly regulated e xpression of transformed genes in a wide variety of model systems incl uding tissue culture cells, bacteria, yeast, Drosophila, and more rece ntly Caenorhabditis elegans. Here we investigate the feasibility of us ing a laser microbeam to induce a sub-lethal heat shock response in in dividual cells of C. elegans. We demonstrate that in transgenic strain s carrying heat shock promoter-lacZ fusions, single cell expression of beta-galactosidase in a variety of cell types of endodermal, mesoderm al, or ectodermal origin can be achieved after pulsing with a laser. A tissue-general, inducible promoter can therefore be converted into on e of single cell specificity which can be induced rapidly at any point in development, offering unique opportunities to study cell-cell inte ractions in C. elegans. This technique defines a new approach to gener ate mosaic animals and may be adaptable to other organisms or tissues.