Figure 3. PfSir2A and PfSir2B Control the Expression of Subtelomeric Genes in P. falciparum .

The expression profile of subtelomeric genes and internal var gene clusters were analysed in Sir2-disrupted lines and applied to a physical map of all 28 chromosome ends. Subtelomeric ends contain most var genes as well as the rifin gene family, which are also known to be antigenically variant. Other gene families occupy subtelomeric regions of P. falciparum chromosomes, but at this stage their biological function or whether they are antigenically variant remains elusive. As seen by the key the colour of each gene relates to the level of expression in each PfSir2-disrupted line. Black genes indicate that expression of that gene is not observed in any condition (expression signal <75th percentile). In the unusual case where PfSir2A or PfSir2B both affected the expression of a single var gene only the most dramatic change is shown. This physical map of gene expression accompanies Figure S3, which graphs the expression values of all subtelomeric genes in 3D7 and the two PfSir2-disrupted lines.