Virginie Orgogozo

Antibody staining of larval gonad and other tissues


Staging larvae - Dissection 
Let flies lay eggs for 4h/ON.
About 64h / three days later, select L2 larvae and put them in a new agar plate with yeast paste.
Every 2h, select the L3 larvae from this agar plate. The L2->L3 molt should be around 72h. Select only female larvae (much smaller gonad).

Dissection
 Pin down the larvae tail in PBT (PBS+0.1% Tween-20) on a Sylgard dissection plate by inserting pins on the head and then the tail
 Cut in the middle of the larvae anterior to the gonad and then along the midline in the posterior part of the body.
 Select a piece of the lateral fat body associated with the gonad. Put it in the little basket in PBT on ice

Fixation, Coloration
 Fix 20min in 5% FA+ EDTA (900uL 5% FA + 100uL EDTA 0.5M)
 Incubate in methanol for 3-5min
 Quick wash in PBT
 PBT 30min
 PBT, 0.1% BSA, 2% GS (20uLGS, 5uL BSA 20% in 1mL PBT) 30min
 Primary antibodies ON at 4°C or 2h at RT (diluted in PBT+BSA+GS)
 3 washes 15min each in PBT
 PBT, 0.1% BSA, 2% GS 1h
 Secondary antibodies 3h at RT (diluted in PBT)
 3 washes 15min each in PBT
 Hoechst (Ryan’s tube) dilution 1/1000 in PBT 45min
 3 washes 15min each in PBT

Mounting
 Put 55uL of Vectashield mounting medium on a slide
 Take the fat body+ovaries with forceps and put them in the Vectashield medium, remove the fat body
 cover with coverslip