Intra-cluster recombination and var transcription switches in the antigenic variation of Plasmodium falciparum

Antigenic variation and immune evasion by Plasmdium falciparum parasitized erythrocytes are mediated by expression switches among members of the multi copy var gene family. Here we describe a cluster of var genes on chromosome 12 that showed spontaneous recombination and switches in the transcription of individual genes. The transcription switches were not associated with s equence changes in promoter regions. Transfected episomes containing a luci ferase reporter under control of a var promoter were expressed regardless o f the transcriptional status of the endogenous promoter. The results sugges t epigenetic regulation of P. falciparum var gene transcription that depend s upon the local structure of chromatin and its associated proteins. (C) 19 99 Published by Elsevier Science B.V.