TY - JOUR A1 - Schulz, Irene A1 - Baumann, Otto A1 - Samereier, Matthias A1 - Zoglmeier, Christine A1 - Gräf, Ralph T1 - Dictyostelium Sun1 is a dynamic membrane protein of both nuclear membranes and required for centrosomal association with clustered centromeres N2 - Centrosomal attachment to nuclei is crucial for proper mitosis and nuclear positioning in various organisms, and generally involves Sun-family proteins located at the inner nuclear envelope. There is still no common scheme for the outer nuclear membrane proteins interacting with Sun I in centrosome/nucleus attachment. Here we propose a model in which Sun1 mediates a physical link between centrosomes and clustered centromeres through both nuclear membranes in Dictyostelium. For the first time we provide a detailed microscopic analysis of the centrosomal and nuclear envelope localization of endogenous Dictyostelium Sun1 during interphase and mitosis. By immunogold electron microscopy we show that Sun1 is a resident of both nuclear membranes. Disruption of Sun1 function by overexpression of full-length GFP-Sun1 or a GFP-Sun-domain deletion construct revealed not only the established function in centrosome/nucleus attachment and maintenance of ploidy, but also a requirement of Sun1 for the association of the centromere cluster with the centrosome. Live-cell imaging visualized the occurrence of mitotic defects, and demonstrated the requirement of microtubules for dynamic distance changes between centrosomes and nuclei. FRAP analysis revealed at least two populations of Sun1, with an immobile fraction associated with the centrosome, and a mobile fraction in the nuclear envelope. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/01719335 U6 - https://doi.org/10.1016/j.ejcb.2009.06.003 SN - 0171-9335 ER - TY - JOUR A1 - Graf, Christine A1 - Raila, Jens A1 - Schweigert, Florian J. A1 - Kohn, Barbara T1 - Effect of leukoreduction treatment on vascular endothelial growth factor concentration in stored canine blood transfusion products JF - American journal of veterinary research N2 - Objective-To evaluate vascular endothelial growth factor (VEGF) concentrations in canine blood products treated with or without a leukoreduction filter. Sample-10 canine blood donors. Procedures-Dogs underwent blood collection. Five of 10 units were leukoreduced prior to separation into packed RBCs and fresh frozen plasma (FFP). Concentrations of VEGF were measured by ELISA in plasma supernatants from aliquots of packed RBCs obtained immediately after separation and on days 7, 14, and 21 of storage. Fresh frozen plasma samples of 2 filtered and 2 nonfiltered units were examined after storage. Results-RBC counts in whole blood before and after leukoreduction did not differ significantly, but WBCs and platelets were removed effectively. The VEGF concentration was lower than the detection limit (9 pg/mL) in 9 of 10 plasma samples and in all packed RBC and FFP units immediately after separation. The median VEGF concentrations in 5 nonfiltered packed RBC units were 37, 164, and 110 pg/mL on days 7, 14, and 21 of storage, respectively. In 5 filtered packed RBC and all FFP units, VEGF concentrations remained lower than the detection limit. Conclusions and Clinical Relevance-Leukoreduction filters were effective in preventing the release of VEGF during storage of canine RBC products. Y1 - 2012 SN - 0002-9645 SN - 1943-5681 VL - 73 IS - 12 SP - 2001 EP - 2006 PB - American Veterinary Medical Association CY - Schaumburg ER -