The Physcomitrella patens system for transient gene expression assays

Abstract

Transient expression assays are valuable techniques to study in vivo the transcriptional regulation of gene expression. These methods allow to assess the transcriptional properties of a given transcription factor (TF) or a complex of regulatory proteins against specifi c DNA motifs, called cis -regulatory elements. Here, we describe a fast, effi cient, and reliable method based on the use of Physcomitrella patens protoplasts that allows the study of gene expression in a qualitative and quantitative manner by combining the advantage of GFP (green fl uorescent protein) as a marker of promoter activity with fl ow cytometry for accurate measurement of fl uorescence in individual cells.