Contents 
xvii Foreword 
Purnell W. Choppin, M.D. 
xviii Trustees, Officers, and Principal Staff Members 
XX Medical Advisory Board 
xxi Scientific Review Board 
xxiii Locations of Howard Hughes Medical Institute Laboratories 
XXV Introduction 
XXV Cell Biology and Regulation Program 
XXXV Genetics Program 
xli Immunology Program 
I Neuroscience Program 
Ivi Structural Biology Program 
W. Maxwell Cowan, M.D., Ph.D. 
1 Electrical Activity of Nerve Cells 
Paul R. Adams, Ph.D. 
5 Three-Dimensional Macromolecular and Cellular Structure 
David A. Agard, Ph.D. 
7 Molecular Mechanisms of Ion Channel Function 
Richard W. Aldrich, Ph.D. 
9 Molecular Mechanisms of Tissue-Specific Hormonal Regulation 
of Gene Expression 
Maria C. Alexander-Bridges, M.D., Ph.D. 
11 Genetic Mechanisms Involved in the Generation of the 
Antibody Repertoire 
Frederick W. Alt, Ph.D. 
13 Molecular Studies of Neurotransmitter Transport and Regulation of 
Neural Gene Expression 
Susan G. Amara, Ph.D. 
15 Control of Cell Fate During Vertebrate Neuronal Development 
David J. Anderson, Ph.D. 
19 Cell Interactions in Neurogenesis 
Spyridon Artavanis-Tsakonas, Ph.D. 
21 The Complement System 
John P. Atkinson, M.D. 
23 The Diversity of Receptor Function 
Richard Axel, M.D. 
25 Developmental Genetics in the Mouse and Human 
Gregory S. Barsh, M.D., Ph.D. 
27 Cell Cycle Control 
David H. Beach, Ph.D. 
Hi 
