title: Bidirectional terminators in Saccharomyces cerevisiae prevent cryptic transcription from invading neighboring genes.
abstract: Transcription can be quite disruptive for chromatin so cells have evolved mechanisms to preserve chromatin integrity during transcription, thereby preventing the emergence of cryptic transcripts from spurious promoter sequences. How these transcripts are regulated and processed remains poorly characterized. Notably, very little is known about the termination of cryptic transcripts. Here, we used RNA-Seq to identify and characterize cryptic transcripts in Spt6 mutant cells (spt6-1004) in Saccharomyces cerevisiae. We found polyadenylated cryptic transcripts running both sense and antisense relative to genes in this mutant. Cryptic promoters were enriched for TATA boxes, suggesting that the underlying DNA sequence defines the location of cryptic promoters. While intragenic sense cryptic transcripts terminate at the terminator of the genes that host them, we found that antisense cryptic transcripts preferentially terminate near the 3΄-end of the upstream gene. This finding led us to demonstrate that most terminators in yeast are bidirectional, leading to termination and polyadenylation of transcripts coming from both directions. We propose that S. cerevisiae has evolved this mechanism in order to prevent/attenuate spurious transcription from invading neighbouring genes, a feature that is particularly critical for organisms with small compact genomes.
authors.affiliation: Institut de recherches cliniques de Montréal, Montréal, Québec H2W 1R7, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Uwimana
authors.affiliation: Institut de recherches cliniques de Montréal, Montréal, Québec H2W 1R7, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Collin
authors.affiliation: Institut de recherches cliniques de Montréal, Montréal, Québec H2W 1R7, Canada.
authors.forename: Célia
authors.initials: C
authors.lastname: Jeronimo
authors.affiliation: Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2M9, Canada.|Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada.|Department of Computer Science, University of Toronto, Toronto, Ontario M5T 3A1, Canada.|Ontario Institute of Cancer Research, Toronto, Ontario M5G 1L7, Canada.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Haibe-Kains
authors.affiliation: Institut de recherches cliniques de Montréal, Montréal, Québec H2W 1R7, Canada.|Département de médecine, Faculté de médecine, Université de Montréal, Québec H3T 1J4, Canada.
authors.forename: François
authors.initials: F
authors.lastname: Robert
mesh_terms: D018388:Codon, Terminator; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D026723:Polyadenylation; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D016385:TATA Box; D014158:Transcription, Genetic
chemical_list: D018388:Codon, Terminator; D012331:RNA, Fungal; D012333:RNA, Messenger