Identification of a Novel Base J Binding Protein Complex Involved in RNA Polymerase II Transcription Termination in Trypanosomes

Rudo Kieft; Yang Zhang; Alexandre P. Marand; Jose Dagoberto Moran; Robert Bridger; Lance Wells; Robert J. Schmitz; Robert Sabatini

521 Monoallelic expression of a VSG ES leads to the expression of a single VSG on the surface of the 522 parasite, a key aspect of the strategy bloodstream form trypanosomes use to evade the host immune 523 system. We have previously shown that the loss of H3.V and J leads to increased expression of VSG 524 genes from silent telomeric BESs (21). This effect is presumably due to the role of these epigenetic marks 525 in attenuating transcription elongation Pol I within the silent VSG BESs, thereby preventing the 526 transcription of silent VSGs. Differential gene expression analysis of RNA-seq reads mapped to the 427 527 genome indicates that the loss of PNUTS leads to increased VSG expression from silent BESs (S2 Table) . Table and S5 Fig). In the VSGnome, these (unknown) VSGs ( Fig 6B) were thought to 542 be primarily located at subtelomeric arrays, but their exact positioning in the genome was not known (78).