Fig 5. Effects of engineered 70-bp repeat sequences on VSG switching and donor selection.

A) BES1 maps of cell lines bearing repeat deletions (Δ70) and introductions, shown as pink boxes, or in reverse (pink arrow). B) Observed switching frequencies of doxycycline induced strains bearing alternative repeat regions: wild-type repeats (70.II, ★), no repeats (Δ70, ●), monomeric motif (Monomer, ◆), dimeric motif (Dimer, ▴), and reverse dimeric motif (Dimer_Rv). Difference in switching between Δ70 and Dimer motif introduction is statistically significant (asterisk over bracket pval = 0.027). C) Flow-cytometry analysis of switched cells (427–2 negative population) and cell cycle (DNA content frequency histogram measured by PI fluorescence) at 48 hours following doxycycline induction. D) VSG-seq analysis of MACS-isolated switchers from three biological replicates of Δ70, Dimer, & Dimer_Rv is shown in the form of a heat diagram where the color intensity reflects the proportion of each VSG RNA in the population. The Lister427 VSG number and its predicted genomic location are shown on the right of the heat diagram where var indicates that the assembled VSG sequence had minor sequence variations from the most similar 427 reference VSG.