Fig. 5

Summary of var gene silencing model. a “Promoter-intron pairing” model. The var intron and promoter are required for var gene silencing. b “Chromatin-spreading” model. Lower expressed var gene exhibits higher heterochromatin marker levels along the gene body. c “Punctuated chromatin” model. Both “Chromatin-spreading” and “Promoter-intron pairing” work for var gene regulation. Lower expressed var genes tend to exhibit higher chromatin accessibility on both intron and 2 kb upstream regions, whereas lower chromatin accessibility can be observed on higher expressed var genes