The soluble nuclear fraction, a highly efficient transcription extract from Drosophila embryos.

We describe the preparation and use of a nuclear extract derived from Drosophila embryos that is highly active for transcription in vitro by RNA polymerase This extract, which is termed the soluble nuclear fraction (SNF), can support multiple rounds of transcription and generate about 0.45 transcripts per template per 30 min. Furthermore, the SNF is deficient in nonspecific DNA binding factors that inhibit transcription, such as histone H1, and can be used for the analysis of transcriptional regulation by promoter- and enhancer-binding factors with either naked DNA or chromatin templates.