Introduction 
THE annual publication of Research 
in Progress has become one of the 
highlights of the Howard Hughes Medi- 
cal Institute's research activities. By pro- 
viding a synoptic overview of the re- 
search being conducted by the Institute's 
investigators, in essentially nontechnical 
language, it has come to be greatly ap- 
preciated not only by those interested in 
the Institute's activities as a Medical Re- 
search Organization, but by many others 
who view it as an accessible introduction 
to current biomedical research. 
The present volume in this series follows fairly 
closely the pattern that has evolved over the past 
three or four years: it provides a snapshot of the 
status of the Institute's research in early 1992. As 
in the previous volume, this issue includes a se- 
ries of introductory essays that are intended to 
assist the reader who has had little or no back- 
ground in biology or medicine. These essays are 
not intended to be exhaustive nor simply to repli- 
cate material readily available in most standard 
biology or medical texts; rather they are intended 
to serve as an expanded glossary of terms, de- 
fining in a general way many of the terms used in 
the individual reports. To emphasize this feature 
of the essays, these technical terms are shown 
in bold type. The essays are based on an initial 
set of drafts prepared for each of the five pro- 
grammatic areas in which the Institute conducts 
research: cell biology and regulation; genetics; 
immunology; neuroscience; and structural biol- 
ogy. The original drafts were kindly prepared by 
Drs. Richard O. Hynes, Philip Leder, Charles A. 
Janeway, Eric R. Kandel, and Stephen C. Harrison, 
respectively. We are grateful to them and to a 
number of their colleagues within the Institute 
who commented on the essays or provided addi- 
tional information and, in some cases, clarified 
ambiguities or corrected errors in the original 
text. As in last year's volume the text of the essays 
has been supplemented by a number of illustra- 
tions, derived for the most part from general texts 
or scientific papers that are identified in the ac- 
companying legends. We hope that these dia- 
grams and photographs will make the essays even 
more useful. 
For readers who wish to know about specific 
research being conducted by HHMI investigators, 
we have provided once again a detailed index. 
The index lists almost every topic or term, from 
abd-A (a gene that directs the segmental develop- 
ment of the abdomen — first identified in the fruit 
fly Drosophila melanogaster) to the zif268 
gene and, in between, the less arcane subjects of 
AIDS, cancer, cystic fibrosis, diabetes, hemo- 
philia, muscular dystrophy, and obesity. Several 
readers have remarked how useful the addition of 
an index has been, and we are grateful once more 
to Diana Witt for preparation of the index. 
The greater part of the volume consists of a 
series of short reports by the investigators asso- 
ciated with the Institute during 1992. This por- 
tion of the volume is again larger than its prede- 
cessor, reflecting the increased number of 
investigators whose work is represented. In addi- 
tion, reports prepared by the Institute's Interna- 
tional Research Scholars are included in a section 
following the investigators' reports. These 24 
scientists are the first recipients of research 
grants awarded under the Institute's new interna- 
tional initiative. The reports submitted by each 
investigator and International Research Scholar 
have been collated and edited by Dr. Claire H. 
Winestock, Senior Scientific Officer; Elizabeth 
Cowley, Copy Editor; William T. Carrigan, Edi- 
tor/Writer; Gail Markley, Manager of Publica- 
tions; and Kimberly A. Cornejo, Permissions Edi- 
tor. Laura North also assisted with the editing of 
manuscripts. We are grateful to them and to the 
many investigators who have provided us with 
suitable illustrations taken from their ongoing re- 
search. Not only do the illustrations help to clar- 
ify the written text, but they also greatly enhance 
the aesthetic appeal of the volume. 
Cell Biology and Regulation Program 
The Cell Biology and Regulation Program is the 
oldest of the Institute's research programs. Origi- 
nally referred to as Metabolic Regulation, which 
reflected the program's roots in clinical studies 
of metabolic and endocrine disorders, the title of 
this program was changed six years ago to reflect 
more accurately its principal theme — the biol- 
ogy of cells, the factors that regulate their normal 
growth and distinctive functions, and the ways in 
which cells interact with each other. In this sense 
the program has come to occupy a critical posi- 
tion in the Institute's research endeavors, and it 
lies firmly within the mainstream of contempo- 
rary biological research. 
