GEOMAGIA50.v3: 2. A new paleomagnetic database for lake and marine sediments

Background: GEOMAGIA50.v3 for sediments is a comprehensive online database providing access to published paleomagnetic, rock magnetic, and chronological data obtained from lake and marine sediments deposited over the past 50 ka. Its objective is to catalogue data that will improve our understanding of changes in the geomagnetic field, physical environments, and climate.Findings: GEOMAGIA50.v3 for sediments builds upon the structure of the pre-existing GEOMAGIA50 database for magnetic data from archeological and volcanic materials. A strong emphasis has been placed on the storage of geochronological data, and it is the first magnetic archive that includes comprehensive radiocarbon age data from sediments. The database will be updated as new sediment data become available.Conclusions: The web-based interface for the sediment database is located at http://geomagia.gfz-potsdam.de/geomagiav3/SDquery.php webcite. This paper is a companion to Brown et al. (Earth Planets Space doi:10.1186/s40623-015-0232-0, 2015) and describes the data types, structure, and functionality of the sediment database

SOUTHWARD SEDIMENT TRANSPORT OF THE PANTHER TONGUE PALEODELTA AND ITS CAUSES

The Cretaceous Panther Tongue sandstone, part of the Star Point Formation, represents a more than fifty-kilometer long, north-south regression into the shallow waters of the western interior seaway. The Panther Tongue is well exposed and studied in the Book Cliffs area, east-central Utah. Its deposits are interpreted as a southward-prograding fluvial-dominated river delta with upward coarsening parasequences. Despite the north-south oriented western shoreline of the western interior seaway, paleocurrents indicate a southward sediment transport direction. This could be explained in three ways: (1) During the early stages of filling the basin, the deposition was parallel to the orogen, but the reduction in accommodation space by initial deposition of the Panther Tongue caused the delta to avulse to the south. A change in flow direction would suggest this. (2) A north-south oriented structural high east of the delta forced a shoreline parallel flow direction because sediment transport was confined to the paleo-low inboard of the proposed high. The indicator for this scenario would be paleoflow direction that reflect consistent southward transport and sedimentary structures and ichnofacies indicative of upward shoaling. (3) The third possibility is that the Panther Tongue represents a north-south-oriented spit that was reworked during the subsequent transgression. Lagoon-like environments as well as lacustrine sediments in the basal portion of the Panther Tongue would support this hypothesis. These three paleogeographic models will be tested by measuring and analyzing several stratigraphic sections and documenting paleocurrent flow directions, sedimentary structures (i.e. flow regimes, grain size), and ichnofacies along an east-west transect within the delta lobe

Role of Cdc48/p97 as a SUMO-targeted segregase curbing Rad51-Rad52 interaction

Cdc48 (also known as p97), a conserved chaperone-like ATPase, plays a strategic role in the ubiquitin system(1-3). Empowered by ATP-driven conformational changes(4), Cdc48 acts as a segregase by dislodging ubiquitylated proteins from their environment(1,2,5). Ufd1, a known co-factor of Cdc48, also binds SUMO (ref. 6), but whether SUMOylated proteins are subject to the segregase activity of Cdc48 as well and what these substrates are remains unknown. Here we show that Cdc48 with its co-factor Ufd1 is SUMO-targeted to proteins involved in DNA double-strand break repair. Cdc48 associates with SUMOylated Rad52, a factor that assembles the Rad51 recombinase on chromatin. By acting on the Rad52-Rad51 complex, Cdc48 curbs their physical interaction and displaces the proteins from DNA. Genetically interfering with SUMO-targeting or segregase activity leads to an increase in spontaneous recombination rates, accompanied by aberrant in vivo Rad51 foci formation in yeast and mammalian cells. Our data thus suggest that SUMO-targeted Cdc48 restricts the recombinase Rad51 by counterbalancing the activity of Rad52. We propose that Cdc48, through its ability to associate with co-factors that have affinities for ubiquitin and SUMO, connects the two modification pathways for protein degradation or other regulatory purposes