Figure 1

Schematic representation of the IT4 var gene repertoire. Gene names, Ups sequence type, domain architecture, chromosomal location, transcription orientation, and binding functions are listed. IT4 var genes are primarily assigned to different groups on the basis of 5' flanking sequence (Ups type) and chromosomal location when known. PfEMP1 proteins are comprised of multiple domains termed N-termimal segment (NTS), Duffy binding-like (DBL), cysteine-rich interdomain region (CIDR), C2, transmembrane (TM), and acidic terminal segment (ATS or exon2) which have been classified by sequence criteria into different types. The PfEMP1 proteins in the 3D7 clone were arbitrarily classified into 17 different protein architectural types on the basis of domain composition [6]. Types 18–25 (bolded) are unique to IT4. Chromosome locations are indicated as T, ST, SST: first, second, and third var genes from the telomere respectively. C: internal var genes. t: transcribed towards telomere, c: transcribed towards centromere. The chromosomal location of var2csa was determined in [78]. Accession numbers for newly sequenced genes are EF158071-EF158105.