Preparation of nuclear extracts from Drosophila embryos

INTRODUCTIONDrosophila nuclear extracts are often used in gene expression studies. They can be used directly as a source of transcription factors, or they can be fractionated, in some cases, to purified proteins. This protocol describes the preparation of a Drosophila embryonic nuclear extract called soluble nuclear fraction (SNF). It uses a low-salt (0.1 M) extraction and produces a relatively low amount of nonspecific DNA-binding proteins. SNF is highly active and is suitable for many in vitro transcription experiments.