RNA 3′ end signals of the S.pombe ura4 gene comprise a site determining and efficiency element.

Humphrey, Tim; Birse, Charles E.; Proudfoot, Nick J.

doi:10.1002/j.1460-2075.1994.tb06529.x

Cited by 38 publications

(58 citation statements)

References 34 publications

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“…6). In keeping with the results of an earlier study of cleavage and polyadenylation in this gene (9), transcripts extending beyond the 3Ј end of the mature ura4 ϩ mRNA were undetectable in control pfs2 ϩ cells grown for 3 h at 36°C (Fig. 6B, upper panel).…”

Section: Vol 25 2005supporting

confidence: 89%

Inactivation of the Pre-mRNA Cleavage and Polyadenylation Factor Pfs2 in Fission Yeast Causes Lethal Cell Cycle Defects

Wang

Asakawa

Win³

et al. 2005

Molecular and Cellular Biology

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Faithful chromosome segregation is fundamentally important for the maintenance of genome integrity and ploidy. By isolating conditional mutants defective in chromosome segregation in the fission yeast Schizosaccharomyces pombe, we identified a role for the essential gene pfs2 in chromosome dynamics. In the absence offunctionalPfs2,chromosomalattachmenttothemitoticspindlewasdefective,withconsequentchromosomemissegregation. Under these circumstances, multiple intracellular foci of spindle checkpoint proteins Bub1 and Mad2 were seen, and deletion of bub1 exacerbated the mitotic defects and the loss of cell viability that resulted from the loss of pfs2 function. Progression from G 1 into S phase following release from nitrogen starvation also required pfs2؉ function. The product of the orthologous Saccharomyces cerevisiae gene PFS2 is a component of a multiprotein complex required for 3-end cleavage and polyadenylation of pre-mRNAs and, in keeping with the conservation of this essential function, an S. pombe pfs2 mutant was defective in mRNA 3-end processing. Mutations in pfs2 were suppressed by overexpression of the putative mRNA 3-end cleavage factor Cft1. These data suggest unexpected links between mRNA 3-end processing and chromosome replication and segregation.Following DNA replication in eukaryotic cells, accurate mitotic chromosome segregation requires the bivalent attachment of the replicated chromosomes to the spindle via sister kinetochores, followed by anaphase movement of the chromosomes to opposite spindle poles. Defects in this process result either in catastrophic failure of mitosis and cell death or in aneuploidy. Spindle checkpoint mechanisms provide protection against these eventualities by imposing a delay over the onset of anaphase until all chromosomes have established symmetrical, bivalent attachments to tense spindle microtubules (14). The molecular basis of this checkpoint is incompletely understood, but many of the proteins involved have been identified and characterized in yeast models and shown to perform analogous checkpoint functions in diverse species, including metazoans and plants. Such proteins include Bub1, Bub3, Mps1, Mad1, Mad2, and Mad3, which are thought to form a heterooligomeric complex at unattached kinetochores (2). During progression through normal, unperturbed mitosis, such complexes would be expected to be short-lived due to the highly dynamic interactions between spindle microtubules and kinetochores. Once all kinetochores have achieved bivalent attachment, the reduction in Mad-and Bub-dependent signaling allows activation of the multisubunit ubiquitin ligase known as the anaphase-promoting complex/cyclosome and subsequent progression into anaphase.Normal chromosome behavior requires the assembly of specialized protein-DNA complexes at telomeres, centromeres, and origins of replication as well as the establishment and maintenance of cohesion between the sister chromatids following DNA replication. The integrity of these chromosome-associated complexes is potentially thre...

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Section: Vol 25 2005supporting

confidence: 89%

Inactivation of the Pre-mRNA Cleavage and Polyadenylation Factor Pfs2 in Fission Yeast Causes Lethal Cell Cycle Defects

Wang

Asakawa

Win³

et al. 2005

Molecular and Cellular Biology

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“…The asymmetry is detectable throughout the lengths of the intergenes but is more pronounced on the downstream (3Ј) side of the coding sequences ( Fig. 2 A and B), presumably because transcription often (but not always) terminates within intergenes (26)(27)(28)(29)(30). A similar strand-specific compositional asymmetry associated with transcription has been observed in introns and in the third position of codons of S. pombe, S. cerevisiae, Arabidopsis thaliana, mouse, and human genes (31).…”

Section: Discussionmentioning

confidence: 99%

DNA replication origins in the Schizosaccharomyces pombe genome

Dai

Chuang

Kelly

2004

Proc. Natl. Acad. Sci. U.S.A.

121

135

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Origins of DNA replication in Schizosaccharomyces pombe lack a specific consensus sequence analogous to the Saccharomyces cerevisiae autonomously replicating sequence (ARS) consensus, raising the question of how they are recognized by the replication machinery. Because all well characterized S. pombe origins are located in intergenic regions, we analyzed the sequence properties and biological activity of such regions. The AT content of intergenes is very high (Ϸ70%), and runs of A's or T's occur with a significantly greater frequency than expected. Additionally, the two DNA strands in intergenes display compositional asymmetry that strongly correlates with the direction of transcription of flanking genes. Importantly, the sequence properties of known S. pombe origins of DNA replication are similar to those of intergenes in general. In functional studies, we assayed the in vivo origin activity of 26 intergenes in a 68-kb region of S. pombe chromosome 2. We also assayed the origin activity of sets of randomly chosen intergenes with the same length or AT content. Our data demonstrate that at least half of intergenes have potential origin activity and that the relative ability of an intergene to function as an origin is governed primarily by AT content and length. We propose a stochastic model for initiation of DNA replication in the fission yeast. In this model, the number of AT tracts in a given sequence is the major determinant of its probability of binding SpORC and serving as a replication origin. A similar model may explain some features of origins of DNA replication in metazoans. T he replicon model postulates that initiation of DNA replication takes place at specific chromosomal sequence elements (replicators) that are recognized by regulatory proteins (initiators) (1). This model was originally proposed to explain features of the replication of prokaryotic cells and viruses and has been validated in such systems by a large body of evidence (2). In eukaryotic cells, DNA replication is initiated from hundreds to thousands of different chromosomal sites in each cell cycle, raising the question of whether the replicon model provides a valid description of the initiation process. Although early genetic studies indicated that DNA replication in the budding yeast Saccharomyces cerevisiae conforms to the main features of the model, it is not yet clear that this is the case for most other eukaryotic species.Origins of DNA replication in S. cerevisiae were identified as sequence elements that conferred the property of autonomous replication on extrachromosomal plasmids (3). Genetic analysis demonstrated that such autonomously replicating sequences (ARS) were Ϸ100 bp in length and contained a common 11-bp consensus sequence essential for origin activity, as well as other sequences that augmented origin activity (3-7). The characterization of S. cerevisiae ARS elements led to the identification of the yeast origin recognition complex (ScORC), the initiator protein that recognizes the ARS-consensus sequence (8). The spe...

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“…The major di¡erence between the two types of signals is the apparent absence of a downstream element in S. cerevisiae. In Schizosaccharomyces pombe, however, a downstream element has been identi¢ed [104]. One should also keep in mind that the elements of the mammalian polyadenylation signals are de¢ned not just by their nucleotide sequences and their positions with respect to the cleavage site, but also by the proteins which bind them.…”

Section: Cleavage and Polyadenylation Signalsmentioning

confidence: 99%

3′-End processing of pre-mRNA in eukaryotes

Wahle¹

1999

FEMS Microbiology Reviews

180

236

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Abstract3P-Ends of almost all eukaryotic mRNAs are generated by endonucleolytic cleavage and addition of a poly(A) tail. In mammalian cells, the reaction depends on the sequence AAUAAA upstream of the cleavage site, a degenerate GU-rich sequence element downstream of the cleavage site and stimulatory sequences upstream of AAUAAA. Six factors have been identified that carry out the two reactions. With a single exception, they have been purified to homogeneity and cDNAs for 11 subunits have been cloned. Some of the cooperative RNA-protein and protein-protein interactions within the processing complex have been analyzed, but many details, including the identity of the endonuclease, remain unknown. Several examples of regulated polyadenylation are being analyzed at the molecular level. In the yeast Saccharomyces cerevisiae, sequences directing cleavage and polyadenylation are more degenerate than in metazoans, and a downstream element has not been identified. The list of processing factors may be complete now with approximately a dozen polypeptides, but their functions in the reaction are largely unknown. 3P-Processing is known to be coupled to transcription. This connection is thought to involve interactions of processing factors with the mRNA cap as well as with RNA polymerase II. ß

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RNA 3′ end signals of the S.pombe ura4 gene comprise a site determining and efficiency element.

Cited by 38 publications

References 34 publications

Inactivation of the Pre-mRNA Cleavage and Polyadenylation Factor Pfs2 in Fission Yeast Causes Lethal Cell Cycle Defects

Inactivation of the Pre-mRNA Cleavage and Polyadenylation Factor Pfs2 in Fission Yeast Causes Lethal Cell Cycle Defects

DNA replication origins in the Schizosaccharomyces pombe genome

3′-End processing of pre-mRNA in eukaryotes

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