Transcriptional and nucleosomal characterization of a subtelomeric gene cluster flanking a site of chromosomal rearrangements in Plasmodium falciparum.

We have recently demonstrated that Plasmodium falciparum chromosomes are compartmentalized into different domains: conserved and polymorphic domains; transcriptionally active and silent domains. Here we have analyzed the transition between these domains at the structural and nucleosomal level. This study was conducted with the end of chromosome 2 that is associated with cytoadherence. At this end of the chromosome, the first set of erythrocytic genes has been mapped 85 kb from the telomere. These genes are monocistronically transcribed as revealed by nuclear run-on analysis. Two of these genes, PfEMP3 and KAHRP, are deleted in cytoadherent negative mutants, whereas the third gene, GLARP, is expressed in all the strains investigated. The data indicate that the polymorphic domain at this end of chromosome 2 extends into the transcribed region. Analysis of the chromatin structure revealed that both the transcribed domain and the subtelomeric region are organized as nucleosomes with a periodicity of 155 +/- 5 bp.