Embryo fixation

[RickJ]

We've recently encountered a problem trying to fix embryos produced by females that over-express oskar (mat-alpha-tubulin-GAL4 driven expression of UAS-osk). We routinely process embryos for a variety of applications by bleach dechorionation (50% bleach:water) followed by fixation in heptane:formaldehyde mix (pretty standard protocol). However, following dechorionation, the embryos from UAS-osk mat-alpha-tubulin-GAL4 females are very sticky and aggregate, refusing to dissociate in either heptane or the aqueous fix phase. As a result the embryos don't fix or stain properly. We've tried rinsing the embryos in PBT (0.1% triton) after dechorionation, but that has minimal effect on embryo aggregation. Has anyone else seen this (with any genotype)? Better yet, does anyone have a suggestion/solution?

[DaniD]

Hi,

Not sure this will be much help, but we had problems fixing embryos in our lab and found that the bleach had gone off, we replaced the bleach with sodium hypochlorite. Might be worth trying. Still, doesn't explain why you are getting sticky embryos with just one of the genotypes though.

Sorry I can't offer anything more inspired!