TY - JOUR A1 - Reynolds, David L. A1 - Hofmeister, Brigitte T. A1 - Cliffe, Laura A1 - Siegel, T. Nicolai A1 - Andersson, Britta A. A1 - Beverley, Stephen M. A1 - Schmitz, Robert J. A1 - Sabatini, Robert T1 - Base J represses genes at the end of polycistronic gene clusters in Leishmania major by promoting RNAP II termination JF - Molecular Microbiology N2 - The genomes of kinetoplastids are organized into polycistronic gene clusters that are flanked by the modified DNA base J. Previous work has established a role of base J in promoting RNA polymerase II termination in Leishmania spp. where the loss of J leads to termination defects and transcription into adjacent gene clusters. It remains unclear whether these termination defects affect gene expression and whether read through transcription is detrimental to cell growth, thus explaining the essential nature of J. We now demonstrate that reduction of base J at specific sites within polycistronic gene clusters in L. major leads to read through transcription and increased expression of downstream genes in the cluster. Interestingly, subsequent transcription into the opposing polycistronic gene cluster does not lead to downregulation of sense mRNAs. These findings indicate a conserved role for J regulating transcription termination and expression of genes within polycistronic gene clusters in trypanosomatids. In contrast to the expectations often attributed to opposing transcription, the essential nature of J in Leishmania spp. is related to its role in gene repression rather than preventing transcriptional interference resulting from read through and dual strand transcription. KW - Trypanosoma-brucei KW - Transcription initiation KW - Messenger RNA KW - DNA KW - Genome KW - Cruzi KW - Hydroxymethyluracil KW - Expression KW - Parasite KW - Glucosyltransferase Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187727 VL - 101 IS - 4 ER -