Fig. 1. Oskimm dictates polar granule morphology. Granule
morphology revealed by signal from GFP-Aub at (A,F) egg-lay,
(B,G) pole bud formation, (C,H) syncytial
blastoderm, (D,I) cellular blastoderm and (E,J)
gastrulation. A and F are at lower magnification to show the majority of the
polar plasm. (K,L) Enlargements of granules shown in E and J,
respectively. Maternal genotypes: A-E, K, osk54/+; F-J, L,
P[oskimm]/+; osk54/Df. In early embryos, the
granules of all genotypes appear essentially the same: small, sand-like and
spread throughout the cytoplasm. At cellular blastoderm and gastrulation,
polar granules in control embryos with either a single endogenous copy of
osk+ (D,E) or no endogenous osk and a single copy
of the P[osk+] transgene (data not shown) have the
characteristic wild-type `donut' appearance. In P[oskimm]/+;
osk54/Df (I,J) or
P[oskimm3'mel]/+;
osk54/Df (data not shown) embryos, the granules fail to form
`donuts' and fuse into one area of granule material per cell. When seen as
serial projections, these areas of granule material appear as a single
continuous aggregate. Scale bar: 2 µm for K,L.