GFP-LD puncta are lipid droplets. (A, B) GFP-LD co-purifies with lipid droplets. (A) Pre-cellularization embryos were embedded in agar and centrifuged. In the image, the embryos are arranged such that the lipid-droplet layer points up. GFP-LD is highly enriched in the droplet layer, whether or not the embryos express endogenous Klar β. Under the same imaging conditions, autofluorescence in wild-type embryos is negligible. (B) Lipid droplets were isolated from wild-type (WT) and GFP-LD expressing (GL) embryos by floatation. Equal amounts of protein from embryo lysates (Lys) and from the droplet fraction (DF) were compared by Western analysis. The cytoplasmic protein tubulin is absent from the droplet fraction. Both the lipid-droplet protein LSD-2 and GFP-LD are highly enriched in the droplet fraction. GFP-LD was detected as in Fig. 5. (C, D) GFP-LD expressing embryos were fixed and stained with Nile Red to reveal lipid droplets. GFP-LD is present in rings around lipid droplets; intensity of GFP-LD signal varies between droplets (scale bar = 5 μm). Panel D shows a magnified view of parts of panel C.
Yu et al. BMC Cell Biology 2011 12:9 doi:10.1186/1471-2121-12-9