RanBP2 and SENP3 function in a mitotic SUMO2/3 conjugation-deconjugation cycle on Borealin

The ubiquitin-like SUMO system controls cellular key functions, and several lines of evidence point to a critical role of SUMO for mitotic progression. However, in mammalian cells mitotic substrates of sumoylation and the regulatory components involved are not well defined. Here, we identify Borealin, a component of the chromosomal passenger complex (CPC), as a mitotic target of SUMO. The CPC, which additionally comprises INCENP, Survivin, and Aurora B, regulates key mitotic events, including chromosome congression, the spindle assembly checkpoint, and cytokinesis. We show that Borealin is preferentially modified by SUMO2/3 and demonstrate that the modification is dynamically regulated during mitotic progression, peaking in early mitosis. Intriguingly, the SUMO ligase RanBP2 interacts with the CPC, stimulates SUMO modification of Borealin in vitro, and is required for its modification in vivo. Moreover, the SUMO isopeptidase SENP3 is a specific interaction partner of Borealin and catalyzes the removal of SUMO2/3 from Borealin. These data thus delineate a mitotic SUMO2/3 conjugation-deconjugation cycle of Borealin and further assign a regulatory function of RanBP2 and SENP3 in the mitotic SUMO pathway

Documenting Bronze Age Akrotiri on Thera using laser scanning, image-based modelling and geophysical prospection

The excavated architecture of the exceptional prehistoric site of Akrotiri on the Greek island of Thera/Santorini is endangered by gradual decay, damage due to accidents, and seismic shocks, being located on an active volcano in an earthquake-prone area. Therefore, in 2013 and 2014 a digital documentation project has been conducted with support of the National Geographic Society in order to generate a detailed digital model of Akrotiri’s architecture using terrestrial laser scanning and image-based modeling. Additionally, non-invasive geophysical prospection has been tested in order to investigate its potential to explore and map yet buried archaeological remains. This article describes the project and the generated results

High-Precision Orientation of Three-Component Magnetic Downhole Logs

The possible benefits of measuring the magnetic flux density in three components continuously along a borehole have been recognized a long time ago by researchers who developed models and interpretation schemes for 3-component magnetic borehole data (Parker and Daniell,1979; Gallet and Courtillot, 1989).Common borehole methods provide data not allowing for an orientation with respect to a global reference, since this requires a highly accurate orienta tion system independent of the magnetic measurements. A first attempt to obtain the orientation of the sonde was made by Bosum et al. (1988) using a mechanical gyro and accelerometers. However, at that time the data quality of the gyro did not allow for a continuous 3-component measurement. Steveling et al. (2003) provide an example from the Hawaii Scientific Drilling Project (HSDP) drill hole, where directional information of magnetization was used to separate massive lavas from hyaloclastites. However, their directional analysis was limited to the inclination because information on the tool rotation around the vertical axis was not available.Here, we describe the successful development of an orientation procedure with very high resolution independent of magnetic data. Test data were acquired in the 2.5-km-deep ICDP Outokumpu Research Hole in eastern Finland (Kukkonen, 2007) with the so-called Göttinger Borehole Magnetometer (GBM). The sonde uses three fiber optic gyros (FOGs) exhibiting a small drift of 1.5°h-1 and a high resolution of 9x10-5 degrees. In combination with a built-in Förster magnetometer triplet, the GBM can record the magnetic field in three components as well as the tool orientation continuously. In the Outokumpu drill hole, errors (root mean square) were 0.14° for the inclination and 1.4° for the declination of the magnetic flux density