Mouse Development I : Organ culture, extraembryonic membranes and gonad dissection Part 1. Extraembryonic membranes and whisker pad organ culture 1. Pregnant female will be sacrificed and 13.5 or 14.5 days post coitus (dpc) embryos removed.
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		3. Identify the whisker pads on the snout by the rows of vibrissa follicles. Slice off using forceps and transfer to small dish of prewarmed HBSS. 4. Most organ culture is performed at the air-fliud interface. The whisker pads are cultured epidermis-side up on collagen- coated micron filters on top of culture media. Culture media is DMEM 10% fetal calf serum, 4 mM glutamine, 0.5 mM pyruvate, 0.1 mM 2-mercaptoethanol, 50 mg/ml gentamicin. We will group whisker pads and culture in (1) media alone, (2) 200 ng/ml FGF7 or (3) 50 ng/ml EGF (substituting for TGFa). Part 2. Dissection and isolation of gonads. 1. Cut embryo in half just below forelimbs using fine scissors. Make a transverse cut down the abdomen. Remove the heart and lungs. Remove the liver. Gently scoop out the stomach and intestines. The gonads should be lying along the back wall connected to two tubes (the mesonephros) and ABOVE the kidneys. If you scooped too vigorously, they will be attached to the back of the gut mass. Carefully remove them and separate from the kidneys (leave attached to the mesonephros). 2. Examine under transmitted light to determine if they are testes (rounder and striped) or ovaries (long and spotty). Examine other samples. Fix by transfering to 4% paraformaldehyde in PBS.