Genome-wide chromosomal association of Upf1 is linked to Pol II transcription in Schizosaccharomyces pombe

Abstract

Although the RNA helicase Upf1 has hitherto been examined mostly in relation to its cytoplasmic role in nonsense mediated mRNA decay (NMD), here we report high-throughput ChIP data indicating genome-wide association of Upf1 with active genes in Schizosaccharomyces pombe. This association is RNase sensitive and it correlates with Pol II transcription and mRNA expression levels. While changes in Pol II occupancy were detected at only some genes in a Upf1-deficient (upf1{Delta}) strain, there is an increased Ser2 Pol II signal at all highly transcribed genes examined by ChIP-qPCR. Furthermore, upf1{Delta} cells are hypersensitive to the transcription elongation inhibitor 6-azauracil and display Pol II abnormalities suggestive of Pol II hyperphosphorylation. A significant proportion of the genes associated with Upf1 in wild-type conditions are also mis-regulated in upf1{Delta}. These data envisage that by operating on the nascent transcript Upf1 might influence Pol II phosphorylation and transcription.