Materials and Reagents

1. E13 embryos from C57BL6J pregnant mice (2 - 4 months old) were electroporated as described below. Animals were collected and handled following the Spanish (RD 223/88), European (86/609/ECC), and American (National Research Council, 1996) regulations.
   
2. Plasmid Midi Kit (Roche, catalog number: 0 3143414001 ) (e.g. Genopure Plasmid Midi Kit)
   
3. Fast green FCF (Sigma-Aldrich, catalog number: F7252 )
   
4. Sterile water
   
5. Isofluorane (Abbott Laboratories, catalog number: 880393.4 )
   
6. Sterile saline (see Recipes)
   
7. 10x phosphate-buffered saline (PBS) (see Recipes)
   

Equipment

1. Borosilicate glass capillaries (World Precision Instruments, catalog number: 1B 100 F-4)
   
2. Micropipette puller (Sutter Instrument, model: P36 )
   
3. Aspirator tube assembly (Sigma-Aldrich, catalog number: A5177-5EA )
   
4. Black braided silk 3/0 (Lorca Marín S.A.Ctra, catalog number: 55159 )
   
5. Sterile gauze and cotton swab (Aposan, catalog number:  343160.6 )
   
6. Dissecting tools (Figure 1C)
   1. Ring forceps (Karl Hammacher GmbH, catalog number: HSC 703-96 )
      
   2. Serrated forceps (Fine Science Tools, catalog number: 11101-09 )
      
   3. Forceps (Fine Science Tools, catalog number: 91150-20
      
   4. Fine scissor (Fine Science Tools, catalog number: 14094-11 )
7. Dissecting microscope (Leica Microsystems, model: MZ125 ) and fiber optic light (LEICA KL 2500 LCD)
   
8. Squared Electroporator (BTX The Electroporation Experts, model: ECM830 )
   
9. Generator Footswitch (BTX The Electroporation Experts, model: 1250FS )
   
10. Platinum plate tweezers-type electrode (Nepa Gene, model: CUY650P5 )
    
11. Isofluorane vaporizer (Surgivet^®, Smiths Medical, model: 100)
    

Procedure