ORCID Profile
0000-0002-1612-9699
Current Organisation
University of Oxford
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Publisher: Springer Science and Business Media LLC
Date: 28-04-2014
Publisher: Elsevier BV
Date: 07-2012
Publisher: The Company of Biologists
Date: 05-2012
DOI: 10.1242/DEV.075440
Abstract: Centrosomes are the principal microtubule organizing centers (MTOCs) of animal cells and comprise a pair of centrioles surrounded by pericentriolar material (PCM). Centriole number must be carefully regulated, notably to ensure bipolar spindle formation and thus faithful chromosome segregation. In the germ line of most metazoan species, centrioles are maintained during spermatogenesis, but eliminated during oogenesis. Such differential behavior ensures that the appropriate number of centrioles is present in the newly fertilized zygote. Despite being a fundamental feature of sexual reproduction in metazoans, the mechanisms governing centriole elimination during oogenesis are poorly understood. Here, we investigate this question in C. elegans. Using antibodies directed against centriolar components and serial-section electron microscopy, we establish that centrioles are eliminated during the diplotene stage of the meiotic cell cycle. Moreover, we show that centriole elimination is delayed upon depletion of the helicase CGH-1. We also find that somatic cells make a minor contribution to this process, and demonstrate that the germ cell karyotype is important for timely centriole elimination. These findings set the stage for a mechanistic dissection of centriole elimination in a metazoan organism.
Publisher: Springer Science and Business Media LLC
Date: 13-04-2017
Abstract: 3D structured illumination microscopy (3D-SIM) is the super-resolution technique of choice for multicolor volumetric imaging. Here we provide a validated s le preparation protocol for labeling nuclei of cultured mammalian cells, image acquisition and registration practices, and downstream image analysis of nuclear structures and epigenetic marks. Using immunostaining and replication labeling combined with image segmentation, centroid mapping and nearest-neighbor analyses in open-source environments, 3D maps of nuclear structures are analyzed in in idual cells and normalized to fluorescence standards on the nanometer scale. This protocol fills an unmet need for the application of 3D-SIM to the technically challenging nuclear environment, and subsequent quantitative analysis of 3D nuclear structures and epigenetic modifications. In addition, it establishes practical guidelines and open-source solutions using ImageJ/Fiji and the TANGO plugin for high-quality and routinely comparable data generation in immunostaining experiments that apply across model systems. From s le preparation through image analysis, the protocol can be executed within one week.
Publisher: The Optical Society
Date: 08-08-2018
DOI: 10.1364/OE.26.021887
Publisher: Proceedings of the National Academy of Sciences
Date: 27-01-2014
Abstract: Polycomb repressor proteins are recruited to the inactive X chromosome in mammals, and this has been attributed to a biochemical interaction between the non–protein-coding RNA X-inactive specific transcript (Xist), which initiates the X inactivation process, and core polycomb subunits. We have studied this using a combination of genome mapping analysis and 3D structured illumination microscopy (3D-SIM) that allows 3D imaging with eightfold volumetric resolution improvement compared with previous state-of-the-art confocal microscopy. Our findings reveal that Xist-mediated recruitment of polycomb repressors does not correlate well with gene silencing and, moreover, that using 3D-SIM, polycomb proteins and Xist RNA show significant spatial separation. These observations challenge prevailing models and prompt a reappraisal of the role of Xist RNA in polycomb recruitment.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 09-2017
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Lothar Schermelleh.