In Vitro Transcription Assay for Archaea Belonging to Sulfolobales

Archaeal transcription and its regulation are characterized by a mosaic of eukaryotic and bacterial features. Molecular analysis of the functioning of the archaeal RNA polymerase, basal transcription factors, and specific promoter-containing DNA templates allows to unravel the mechanisms of transcription regulation in archaea. In vitro transcription is a technique that allows the study of this process in a simplified and controlled environment less complex than the archaeal cell. In this chapter, we present an in vitro transcription methodology for the study of transcription in Sulfolobales. It is described how to purify the RNA polymerase and the basal transcription factors TATA-binding protein and transcription factor B of Saccharolobus solfataricus and how to perform in vitro transcription reactions and transcript detection. Application of this protocol for other archaeal species could require minor modifications to protein overexpression and purification conditions.