Fig. 1.
Adenoviral-mediated expression of c-myc-tagged mutants of small GTPases in chick motor neurons. A, Motor neurons from 6-d-old chick embryos were plated on fibronectin and infected with a recombinant adenovirus carrying c-myc-tagged constitutively active rac1 under the viral E1A promoter (V12rac1-AdE1A). Three days after infection, c-myc immunoreactivity is present in growth cones and cell bodies (data not shown) of motor neurons. B, In lacZ-AdE1A-infected cultures, c-myc immunostaining was very faint, indicating very little unspecific staining using the anti-c-myc antibody. C, Motor neuron cultures were infected with V12rac1-AdE1A using a multiplicity of infection (moi or ratio of virus particles to neurons) of 20, 50, and 100. Three days after infection, cultures were solubilized, and extracted proteins were separated by 15% SDS-PAGE. After transfer to PVDF membranes, the presence ofV12rac1 was demonstrated using a rac1-specific antibody.D, Rac1-immunoreactive bands were quantified by densitometric analysis and normalized to the values at 20 moi. Total rac1 immunoreactivity was proportional to the moi.