Extended Data Fig. 6. Creation of VSGsur and VSGsur mutant expressing strains.

The same construct was used multiple times to generate different VSG-expressing cell lines. The top schematic shows the endogenous sub-telomeric expression site in 2T1 cells, which express VSG2 (pink) with its endogenous UTRs (dark green). The vector used to integrate new VSGs was adapted from Pinger et al.², wherein the homology directed integration of a novel VSG ORF (black) flanked by the UTRs of VSG2 is mediated by 3′ telomere seeds (Tel-S) and 5′ homology to the upstream co-transposed region (CTR – teal). Transfected cells are identified by screening for the integration of a hygromycin selection cassette (red) that is expressed via read-through transcription driven by the subtelomeric promoter.