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. Author manuscript; available in PMC: 2012 Mar 23.
Published in final edited form as: Nat Cell Biol. 2011 Apr 10;13(5):550–558. doi: 10.1038/ncb2225

Figure 2. TFG-1 localizes to ER exit sites that are juxtaposed to the Golgi.

Figure 2

(a) Dissected C. elegans gonads were fixed and stained using Cy2-labeled α-TFG-1 and Cy3-labeled α-SEC-16 antibodies (n=8). Both individual and merged images of proximal oocytes with TFG-1 in green and SEC-16 in red are shown (Bar, 10 μm). The upper right image is the boxed area in the panel below magnified 6× (Bar, 2 μm). Also shown is a schematic of the C. elegans reproductive system, which includes a syncytial stem cell niche in the distal gonad (boxed region in light green) and proximal oocytes that have undergone cellularization (boxed region in dark green). (b and c) Lowicryl sections of C. elegans oocytes were stained with antibodies against TFG-1 or a combination of TFG-1 and SEC-13 antibodies. Arrows highlight Golgi cisternae. Large arrowheads point out 15 nm gold particles associated with immunoreactive TFG-1, and small arrowheads highlight 5 nm gold particles associated with SEC-13. Bars, 100 nm. An inset is provided in panel c to clearly show the distribution of 5 nm particles at higher magnification (Inset bar, 15 nm). In addition, a three-dimensional reconstruction of TFG-1 immunolocalization is shown. The image was generated using the software Reconstruct from serial 50 nm thin sections. Vesicles were reconstructed using the sphere setting, and all other components (ER, ERGIC, coats, Golgi stacks) were generated using the Boissonnat surface setting. Light grey: ER; dark grey: COPII coat; orange: ER-derived transport vesicles and ERGIC; red, green and blue: Golgi cisternae; from cis to trans, respectively. (d) An electron micrograph illustrating two ER exit sites and adjacent Golgi complexes in the proximal most oocyte of an animal following high pressure freezing and freeze substitution (Bar, 500 nm). On the right is a three-dimensional reconstruction of the same pair of Golgi complexes and associated ER exit sites. The ER exit sites are surrounded by vesicles that fuse to form the ERGIC. Light grey: ER; dark grey: COPII coat; orange: ER-derived transport vesicles and ERGIC; yellow, red and blue: Golgi cisternae; from cis to trans, respectively.