Characterization of VSG Gene Expression Site Promoters and Promoter-Associated DNA Rearrangement Events

The expressed variant cell surface glycoprotein (VSG) gene of Trypanosoma brucei is located at the 3′ end of a large, telomeric, polycistronic transcription unit or expression site. We show that the region 45 kb upstream of the VSG gene, in the expression site on a 1.5-Mb chromosome, contains at least two promoters that are arranged in tandem, directing the transcription of the expression site. DNA rearrangement events occur specifically, at …