3,579 research outputs found
Composition and Dynamics of the Eukaryotic Replisome: A Brief Overview
No full textHigh-fidelity chromosomal DNA replication is vital for maintaining the integrity of the genetic material in all forms of cellular life. In eukaryotic cells, around 40-50 distinct conserved polypeptides are essential for chromosome replication, the majority of which are themselves component parts of a series of elaborate molecular machines that comprise the replication apparatus or replisome. How these complexes are assembled, what structures they adopt, how they perform their functions, and how those functions are regulated, are key questions for understanding how genome duplication occurs. Here I present a brief overview of current knowledge of the dynamic molecular events underlying chromosomal DNA replication in eukaryotic cells and how these events are regulated
Purification and functional inactivation of the fission yeast MCMMCM–BP complex
No full textAbstractThe MCM (mini-chromosome maintenance) complex is the core of the eukaryotic replicative helicase and comprises six proteins, Mcm2–Mcm7. In humans, a variant form of the complex has Mcm2 replaced by the MCM–BP protein. Recent results suggest that a similar complex exists in fission yeast with an essential role in DNA replication and cell cycle progression. Here, we describe the purification and subunit composition of the fission yeast MCMMcb1 complex. Using newly generated temperature-sensitive alleles, we show that loss of MCMMcb1 function leads to accumulation of DNA damage, checkpoint activation and cell cycle arrest, and provide evidence for a role for MCMMcb1 in meiosis.Structured summary of protein interactionsMcb1 physically interacts with Mcm4 by pull down (View interaction)Mcb1 physically interacts with Mcm5 by pull down (View interaction)Mcb1 physically interacts with Mcm6 by pull down (View interaction)Mcm4 and Mcb1 physically interact by bimolecular fluorescence complementation (View interaction)Mcb1 physically interacts with Mcm3, Mcm4, Mcm5, Mcm6 and Mcm7 by tandem affinity purification (View interaction)Mcb1 physically interacts with Mcm7 by pull down (View interaction
Genetics of lagging strand DNA synthesis and maturation in fission yeast:suppression analysis links the Dna2-Cdc24 complex to DNA polymerase delta
No full textThe Cdc24 protein is essential for the completion of chromosomal DNA replication in fission yeast. Although its precise role in this process is unclear, Cdc24 forms a complex with Dna2, a conserved endonuclease-helicase implicated in the removal of the RNA-DNA primer during Okazaki fragment processing. To gain further insights into Cdc24-Dna2 function, we screened for chromosomal suppressors of the temperature-sensitive cdc24-M38 allele and mapped the suppressing mutations into six complementation groups. Two of these mutations defined genes encoding the Pol3 and Cdc27 subunits of DNA polymerase delta. Sequence analysis revealed that all the suppressing mutations in Cdc27 resulted in truncation of the protein and loss of sequences that included the conserved C-terminal PCNA binding motif, previously shown to play an important role in maximizing enzyme processivity in vitro. Deletion of this motif is shown to be sufficient for suppression of both cdc24-M38 and dna2-C2, a temperature-sensitive allele of dna2(+), suggesting that disruption of the interaction between Cdc27 and PCNA renders the activity of the Cdc24-Dna2 complex dispensable.</p
The archaeo-eukaryotic GINS proteins and the archaeal primase catalytic subunit PriS share a common domain
No full textThis work was funded by the Scottish Universities Life Sciences Alliance (SULSA).Primase and GINS are essential factors for chromosomal DNA replication in eukaryotic and archaeal cells. Here we describe a previously undetected relationship between the C-terminal domain of the catalytic subunit (PriS) of archaeal primase and the B-domains of the archaeo-eukaryotic GINS proteins in the form of a conserved structural domain comprising a three-stranded antiparallel beta-sheet adjacent to an alpha-helix and a two-stranded beta-sheet or hairpin. The presence of a shared domain in archaeal PriS and GINS proteins, the genes for which are often found adjacent on the chromosome, suggests simple mechanisms for the evolution of these proteins.Peer reviewe
No. 617 Stuart Ruckman
No full textTranscript (12, 40 pages) of two interviews by Matt Driscoll with Stuart Ruckman on April 9, 2010, and July 7, 2011Ruckman (b. 1966) was born in Salt Lake City, Utah. Stuart shares how his family, particularly his father, played a significant role in introducing him to the outdoors. Some of his initial explorations included a hike to the top of Mount Olympus when he was five years old, backpacking trips in the Wasatch and Uinta Mountains, and a successful summit attempt on the Grand Teton when he was twelve. Stuart discovered technical rock climbing due to the influence of his older brother Bret, five years Stuart\u27s senior. Bret learned under Dennis Turville, a well-respected Salt Lake climbing instructor. Stuart shares his observations on the Salt Lake climbing community of the late 1970s and 1980s, noting the intimacy of the community, while also pointing out the significant influence of a handful of climbers, including Merrill Bitter, Les Ellison, and Brian Smoot. He briefly describes the proliferation of new-route development in the Wasatch during his first decade in climbing. In collaboration with his brother Bret, Stuart published comprehensive guidebooks on climbing in the Wasatch Mountains. Stuart\u27s contributions as a first-ascensionist and co-author of Rock Climbing the Wasatch Range attest to his lasting impact on Utah climbing. Interview is part of the Outdoor Recreation History Project. Interviewer: Matt Driscol
George MacLeod’s open-air preaching: performance and counter-performance
No full textStuart Blythe uses the methodology of performance to analyse George MacLeod’s open-air preaching. He points out that MacLeod’s preaching was derived from a theology of the incarnation, and an understanding of the paradoxes and dichotomies of common human life. This preaching, Blythe suggests, was also a counter-performance in the context of outlooks and ideologies inimical to the gospel. The paper raises interesting issues related to preaching as performance, and the further question as to whether or not the life and work of the Church as a whole might now be better understood as a counter-performance.Publisher PD
Redemption in the work of Francis Stuart
No full textThe idea of redemption is central to an understanding of the work
of Francis Stuart. Through an examination of its development and
expression, it is possible to demonstrate the integrity of his work and
its distinctive qualities. Such a demonstration is necessary because
Stuart's writing has been subjected to comparatively little scholarly
inquiry, although reviews of his work, especially that produced since
1949, suggest that it is impressive and important.
First, a general background to Stuart's work, a discussion of the
special problems associated with reading it, and a summary of his corpus
is provided. This indicates that the idea of redemption is important to
his earliest writing. The state of redemption is shown to be a
necessary apotheosis for Stuart's outcast heroes; it involves spiritual
suffering through which may be found a sense of reintegration and a
higher reality. This is expressed through interrelated themes such as
those of gambler, artist and ordinary man; mystic and criminal; sacred
and profane love; and spirituality and the mundane. The nature of the
redemptive experience is further elaborated by distinctive, complex
motifs, especially the hare, the ark and the woman-Christ. Their
recurrence provides an important element in the unity of Stuart's work.
Because Stuart's idea of the outcast raises important biographical
questions, an examination of the relationship between Stuart's life and
his work is made. Finally, the way in which the idea of redemption
exists in the language structures of Stuart's novels is examined, with
especial reference to his most recent work, The High Consistory. The
thesis shows that the development of the these of redemption
demonstrates the integrity of Stuart's work
Does the amount of participation matter? Public comments, agency responses and the time to finalize a regulation
No full textThe notice and comment rulemaking process is a fundamental part of how agencies write regulations. While this process is starting to receive more empirical attention, the question of how the number of comments that an agency receives affects its decision-making process has received little examination. This paper uses Boolean analysis to examine nine rules from two agencies at the Department of Health and Human Services and evaluates the impact of a high volume of comments on agency changes to proposed rules and the time an agency takes to finalize a proposed rule. These nine cases suggest that agencies are most likely to change their proposals when they receive a high volume of comments on highly complex rules that are not very politically salient. Highly complex rules are also likely to take a long time to finalize when there are many public comments however it is often other factors that cause a long delay between proposed and final rules.Peer reviewedThe final publication is available at Springer via http://dx.doi.org/10.1007/s11077-007-9051-
The fission yeast <em>pfh1</em> gene encodes an essential 5' to 3' DNA helicase required for the completion of S-phase
No full textThe Cdc24 protein plays an essential role in chromosomal DNA replication in the fission yeast Schizosaccharomyces pombe, most likely via its direct interaction with Dna2, a conserved endonuclease-helicase protein required for Okazaki fragment processing. To gain insights into Cdc24 function, we isolated cold-sensitive chromosomal suppressors of the temperature-sensitive cdc24-M38 allele. One of the complementation groups of such suppressors defined a novel gene, pfh1(+), encoding an 805 amino acid nuclear protein highly homologous to the Saccharomyces cerevisiae Pif1p and Rrm3p DNA helicase family proteins. The purified Pfh1 protein displayed single-stranded DNA-dependent ATPase activity as well as 5' to 3' DNA helicase activity in vitro. Reverse genetic analysis in S.pombe showed that helicase activity was essential for the function of the Pfh1 protein in vivo. Schizosaccharomyces pombe cells carrying the cold-sensitive pfh1-R20 allele underwent cell cycle arrest in late S/G2-phase of the cell cycle when shifted to the restrictive temperature. This arrest was dependent upon the presence of a functional late S/G2 DNA damage checkpoint, suggesting that Pfh1 is required for the comple tion of DNA replication. Furthermore, at their permissive temperature pfh1-R20 cells were highly sensitive to the DNA-alkylating agent methyl methanesulphonate, implying a further role for Pfh1 in the repair of DNA damage.</p
Ep. #174 - Stuart Gibbs
No full textThis recording and transcript form part of a collection of podcasts conducted by the Cultures of Energy at Rice University. Cultures of Energy brings writers, artists and scholars together to talk, think and feel their way into the Anthropocene. We cover serious issues like climate change, species extinction and energy transition. But we also try to confront seemingly huge and insurmountable problems with insight, creativity and laughter.FINALLY an episode of the Cultures of Energy podcast that is for once totally wholesome and family-friendly and appropriate to listen to with your kids! Cymene and Dominic share their own thoughts about talking to children about climate change. And then (13:51) we welcome an author that will be well known (especially to listeners aged 8-12 and their families), Stuart Gibbs, the author of the very popular FunJungle, Spy School and Moonbase Alpha middle grade series. Stuart has thematized both climate change and animal conservation in his books and we talk to him about how readers have responded to those interventions, about his writing process in general, and why he thinks it’s important for adults to talk to children honestly about our environmental challenges. If you happen to be in the Houston area on April 30th, please check out Stuart’s reading at the Blue Willow Bookstore, deets here: https://www.bluewillowbookshop.com/event/stu-gibbs-0 PS And, as promised, here are some solid online resources for teaching especially younger kids about climate change and climate action: http://climatechangeconnection.org/resources/climate-friendly-schools/resources-for-schools/; https://www.commonsense.org/education/articles/4-free-tools-to-teach-about-climate-change; https://www.earthguardians.org/50simplethings/; https://thinkprogress.org/how-to-talk-to-a-5-year-old-about-climate-change-ef8ec30b1bd1
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