Transcription hinders replication fork progression and stability, and the Mec1/ATR checkpoint protects fork integrity. Examining checkpoint-dependent mechanisms controlling fork stability, we find that fork reversal and dormant origin firing due to checkpoint defects are rescued in checkpoint mutants lacking THO, TREX-2, or inner-basket nucleoporins. Gene gating tethers transcribed genes to the nuclear periphery and is counteracted by checkpoint kinases through phosphorylation of nucleoporins such as Mlp1. Checkpoint mutants fail to detach transcribed genes from nuclear pores, thus generating topological impediments for incoming forks. Releasing this topological complexity by introducing a double-strand break between a fork and a transcribed unit prevents fork collapse. Mlp1 mutants mimicking constitutive checkpoint-dependent phosphorylation also alleviate checkpoint defects. We propose that the checkpoint assists fork progression and stability at transcribed genes by phosphorylating key nucleoporins and counteracting gene gating, thus neutralizing the topological tension generated at nuclear pore gated genes.
Pubmed ID: 21784245 RIS Download
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Open source Java based image processing software program designed for scientific multidimensional images. ImageJ has been transformed to ImageJ2 application to improve data engine to be sufficient to analyze modern datasets.
View all literature mentionsOsprey is a software platform for visualization of complex interaction networks. Osprey builds data-rich graphical representations from Geno Ontology (GO) annotated interaction data maintained by The Grid. The following list describes some of the important characteristics of the Osprey Network Visualization System: * Portability ( cross platform availability ) o Osprey is available on almost all Platforms that support the latest Java Plugin * Tools for Biological Analysis o Osprey provides many features such as network filters, connectivity filters, advanced layouts, and dataset superimposing which are extremely useful to biologists who are interested in analyzing their data * Powerful Support Database o Integrated with Osprey is a powerful database of interactions and annotation, see section 8. The GRID ( The General Repository of Interaction Datasets ). * Ease of use o Osprey provides an extremely user friendly interface for working with interaction data * Online Database Add-on Ability o Osprey can be incorporated as a standard visualization tool with online databases such as The GRID * Support for figures o Osprey networks can be saved in SVG, PNG and JPG format so they can be used with image programs Sponsors: Development of Osprey was funded by a grant from the Canadian Institutes of Health Research.
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