THE NERVE GROWTH FACTOR PRECURSOR PRONGF EXHIBITS NEUROTROPHIC ACTIVITY SIMILAR TO THAT OF MATURE NERVE GROWTH FACTOR Margaret Fahnestock 1,2 *, Guanhua Yu 1 , Bernadeta Michalski 1 , Silvy Mathew 2 , Amy Colquhoun 3 , Gregory M. Ross 3 and Michael D. Coughlin 1 1 Departments of Psychiatry and Behavioural Neurosciences and 2 Biology, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada, and 3 Department of Physiology, Queen's University, Kingston, Ontario, K7L 3N6, Canada. *To whom correspondence should be addressed at: Department of Psychiatry and Behavioural Neurosciences McMaster University 1200 Main Street West Hamilton, Ontario L8N 3Z5 Canada Tel.: 1-905-525-9140, ext. 23344 Fax: 1-905-522-8804 E-mail: fahnest@mcmaster.ca