The European Molecular Biology Laboratory (EMBL) is one of the highest ranked scientific research organizations in the world. The Headquarters Laboratory is located in Heidelberg (Germany) and the outstations are in Grenoble (France), Hamburg (Germany), Hinxton (UK) and Monterotondo (Italy).

Description

A comprehensive view of the mitotic apparatus in vertebrate cells is essential to understand the processes involved in chromosome segregation. Xenopus egg extracts have been used extensively for studying the process of bipolar spindle assembly (Murray, 1991). Yet, an image of the spindle at the resolution of single microtubule (MT) is still missing, which inhibits progress in the field. Urgent questions cannot be answered because we do not know if pole-to-pole bundles are made of many short-overlapping MTs or of few long ones. We also ignore where the minus ends, i.e. nucleation sites of MTs, are located across the spindle. Thus, although the spindle is a dynamic structure, a high-resolution steady state image must be obtained in order to provide major clues allowing us to build a computational model of metaphase organization. Electron tomography (ET) and especially large-scale electron tomography developed in the Antony team is needed and essential to obtain real reconstructions of spindle volume which will serve as a primary data base resolving all microtubules at EM resolution. The Antony lab has recently reconstructed the full cell volume of the fission yeast (Höög and Antony, 2007; Höög et al., 2007) as well as carried out complementary investigations on their MT behaviour (Höög et al., 2011, Roque et al. 2010). Also, EMBL is very well equipped for plastic ET with a 300 kV microscope in the EM Core Facility. The post doc will work at generating tomograms from Xenopus spindles assembled in egg extracts. These tomograms will then be processed for image analysis by segmentation of sub-volumes in order to reconstruct the microtubules and their connections, in particular with the chromosomes and the spindle poles. Quantitative parameters will need to be extracted from the generated models so as to derive measurements of MT lengths, angles and respective distances in between them. From such numbers categories of MTs can be found out and various MT subpopulations defined, depending on their length, position and interaction with other MTs, chromosomes and spindle poles. This analytical part, which involves many aspects of computing, requires a well trained person able to handle computational analysis of the tomograms. These data will establish a structural reference for the Xenopus spindle from which computer models of spindle dynamics can later be built (Nédélec et al. 2003). The chance to combine the various approaches needed in the project, cryofixation, correlative microscopy, electron tomography and image analysis, to bring up a comprehensive view of the Xenopus spindle, is unique to EMBL. Qualifications and Experience A PhD and previous experience in image analysis of EM/Electron Tomography or cryoEM data is required. First author publication is expected. Strong motivation to work in an interdisciplinary and international environment is essential.

Benefits

EMBL is an inclusive, equal opportunity employer offering attractive conditions and benefits appropriate to an international research organisation. Please note that appointments on fixed term contracts can be renewed, depending on circumstances at the time of the review.

Additional Job Details

Please apply online through www.embl.org/jobs