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. Author manuscript; available in PMC: 2014 Jul 15.
Published in final edited form as: Dev Biol. 2013 Apr 4;379(2):139–151. doi: 10.1016/j.ydbio.2013.03.019

Figure 4. PGCs are required for SGP wrapping, and PGCs and endoderm are required for SGP positioning and projection morphology.

Figure 4

Stills from a 4D confocal movie of embryos of the indicated genotype expressing hnd-1P::GFP-PHPLC1∂1 (SGPs), end-1P::mCherry-PHPLC1∂1 (endoderm), and nmy-2P::PGL-1::RFP (PGC-specific P-granules). PGCs are indicated with asterisks. See Fig. 1G-J for comparison to wild type. (A–C) Arrowheads mark P-granules in transformed PGCs. (A) In mes-1(RNAi) embryos, SGPs extend thicker projections (arrows in A,B), (B) and do not migrate quite as far posteriorly (dashed line indicates distance migrated from average SGP birth location). (C) SGPs continue to extend projections and fail to transition to wrapping behaviors. (D) Quantification of SGP and PGC position in indicated genotypes. Data for end-1 end-3 embryos is divided into those with internal PGCs “int” (solid gray rectangle) and external PGCs “ext” (hatched gray rectangle). The median (line in box), 25th and 75th percentiles (box boundaries), and standard deviation (error bars) are shown. The SGP birth locations were not significantly different between the four categories. The difference between SGP birth and end location was significant for each category. The difference between wild-type SGP end location and the end locations for the other three genotypes was also significant (p<0.001, two-tailed Student’s t-test). (E–H) (E) In end-1 end-3 embryos, the SGPs extend shorter, thicker projections (arrows), (F) and do not migrate as far posteriorly (dashed line indicates distance migrated from average SGP birth location). SGPs can shift more medially and come in contact with each other (arrows in F,G). (G) SGPs eventually wrap around PGCs. Expression of hnd-1P::GFP-PHPLC1∂1 in a misplaced non-SGP cell is indicated (#). (H) In end-1 end-3 embryos with PGCs external, SGPs extend short projections (arrowheads) but fail to wrap around any cell. (I) end-1 end-3 embryo in which one SGP contacts both PGCs, and one PGC is briefly wrapped by both SGPs (arrows). Scale bars are 5μm.