Project description:Hrp3_Purification from Schizosaccharomyces pombe 972h- Eukaryotic genome is composed of repeating units of nucleosomes to form chromatin arrays. A canonical gene is marked by nucleosome free region (NFR) at its 5’ end followed by uniformly spaced arrays of nucleosomes. In fission yeast we show both biochemically and in vivo that both Hrp1 and Hrp3 are key determinants of uniform spacing of genic arrays.
Project description:Polyadenylation of pre-mRNAs, a critical step in eukaryotic gene expression, is mediated by cis elements, collectively called the polyadenylation signal. Genome-wide analysis of such polyadenylation signals was missing in fission yeast, which is an important model organism. We demonstrate that the canonical AATAAA motif is the most frequent and functional polyadenylation signal in Schizosaccharomyces pombe. Using analysis of RNA-Seq datasets from cells grown under various physiological conditions, we identify 3' UTRs for nearly 90% of the yeast genes. Heterogeneity of cleavage sites is common, as well as alternative polyadenylation within and between conditions. We validated the computationally identified sequence elements likely to promote polyadenylation, by functional assays including qRT-PCR and 3'RACE analysis. The biological importance of the AATAAA motif is underlined by functional analysis of genes containing it. Furthermore, it has been shown that convergent genes require trans elements, like cohesin for efficient transcription termination. Here we show that convergent genes lacking cohesin are generally (on chromosome 2) associated with longer overlapping mRNA transcripts. Our bioinformatic and experimental genome-wide results are summarized and can be accessed and customized in a user-friendly database Pomb(A).
