Increasing evidence in literature reveals that the organization of chromosomal domains in the cell nucleus plays an important role in gene expression during cellular differentiation and development (Spector, 2003, Taddei et al, 2004). Fluorescent in situ DNA hybridization (FISH) allows to study the positioning of single copy genes into the nucleus, and is therefore widely applied to address the question of how is gene positioning regulated.
We describe here a two-colour FISH method for interphase nuclei of whole mount drosophila embryos. This procedure has been adapted from the protocol described by Gemkow et al, 1998, and allows us to study the relative position of two distinct single copy genes in the nucleus. This FISH protocol can be applied to other drosophila tissues, such as larval imaginal discs (Bantignies et al, 2003). For simplicity, we will use "tissues" throughout the text to design embryos and larval discs in the steps common to all tissues, whereas we will specify "embryos" or "larval imaginal discs" in those steps that apply to only one type of tissue.
Institute of Human Genetics
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