XB-IMG-129224
Xenbase Image ID: 129224
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Figure 4. Actin disruption results in sedimentation and fusion of nuclear bodiesa, 2D MSD of RNP bodies shows highly constrained motion in native GVs (circles). Red: nucleoli (R>2 μm) (11 z-positions from 5 GVs, 320 bodies identified) and green: HLBs (16 z-positions from 10 GVs, 232 bodies identified). In latrunculin-treated GVs (squares) these RNP bodies are more mobile. Red: nucleoli (R>2 μm) (10 z-positions from 6 GVs, 442 bodies identified) and green: HLBs (9 z-positions from 5 GVs, 149 bodies identified). Inset shows a few large nucleoli embedded in an F-actin meshwork visualized by Lifeact::GFP. Scale bar = 10 μm. b, A sub-population of small nucleoli (“micronucleoli,” R<2 μm) are more mobile, and occasionally exhibit intermittent dynamics (“cage hopping”) in native GVs. Inset shows micronucleoli inside a meshwork labeled with Lifeact::GFP. (n=number of displacements at a given lag time per nucleolar size from 11 z-positions from 7 GVs, 240 bodies identified). Error bars = s.e.m. Scale bar = 10 μm. c, Left column shows example X-Y trajectories for a representative micronucleolus (top) and a typical large nucleolus (bottom). The right column shows corresponding temporal changes in position, X(t) and Y(t). For d–h, top images show a maximum intensity projection of a 100-micron thick section of nucleoli labeled with NPM1::RFP (red) and HLBs labeled with GFP::Coilin (green), and bottom images show a 3-D rendering in the X-Z plane. d, Nucleoli and HLBs are suspended in an untreated GV. For e–g, time-lapse images are from the same GV from a Lat-A treated oocyte; time refers to minutes after dissection. h, Large nuclear bodies that form overnight after actin disruption by Lat-A. Scale bar = 50 μm. 3D grid size = 50 μm. i, 3D representation of nucleoli (top) and HLB (bottom) trajectories after actin disruption in the GV shown in e–g. j, The vertical position of nuclear bodies (red: nucleoli R>2 μm, and green: HLBs) from i as a function of time. k, The sedimentation velocity plotted against normalized size. Black: metallic R=0.5 μm beads (n=16 movies of 16 GVs, 237 tracks analyzed), red: nucleoli (R>2 μm) (n=17 movies of 16 GVs, 394 tracks analyzed) and green: HLBs (n=18 movies of 12 GVs, 149 tracks analyzed). Larger circles represent binned data points and solid lines are linear fits of the data, with the slope representing the buoyant density. Error bars = s.d. Image published in: Feric M and Brangwynne CP (2013) Image downloaded from an Open Access article in PubMed Central. Image reproduced on Xenbase with permission of the publisher and the copyright holder. Larger Image Printer Friendly View |