Aron A. Moscona, PhD, 1921-2009

A renowned developmental biologist who was one of the first to show how cellsrecognize each other and interact, Aron A. Moscona, PhD, the Louis Block ProfessorEmeritus of molecular genetics and cell biology and of pathology at the Universityof Chicago and a member of the U.S. National Academy of Science, died from heartfailure January 14 in Manhattan. He was 87.

Moscona was best known for a series of experiments that revealed how cellsarrange themselves to form tissues or organs in the body. He developed techniquesto separate cells at early stages of development, suspend them in fluid andallow them to grow back together. He showed that the individual cells from anorgan can find each other and reassemble properly, "like parts," hesaid, "of an animated jigsaw puzzle," and that specific moleculeson cell surfaces govern these interactions during development.

Moscona's work, beginning at Strangeways Research Laboratory in Cambridge, England,in 1952, and continuing at the University of Chicago from 1958 to 1992, influenceda generation of scientists. Many of today's leading developmental biologistswere stimulated to pursue scientific careers after hearing him speak about cellsand organ development. "He was working in that specialty before the toolsof that field had even been developed," said Linda Degenstein, a technicianwho worked in Moscona's laboratory for decades.

"Aron Moscona's efforts were extraordinarily imaginative, wide rangingin scope and truly of seminal significance for the field of developmental biology,"said Donald Steiner, MD, the A.N. Pritzker Professor of Biochemistry and MolecularBiology and a member of the Howard Hughes Medical Institute at the Universityof Chicago.

"Moscona did fundamental work that was way ahead of his time, with significanceextending basic biology into areas such as cancer metastasis," said colleagueRalph Weichselbaum, MD, the Ludwig Professor and chairman of radiation and cellularoncology at the University of Chicago. "He was also a decent guy. Somefound him a bit brusque, but he extended a lot of guidance and support to mewhen I first came to the University."

"Aron's pioneering research in tissue and organ development set thefoundations for decades of subsequent molecular studies in this field, and alsoprovided enduring insights into cancer progression," said Elaine Fuchs,PhD, a former colleague of Moscona at the University of Chicago and now theRebecca C. Lancefield Professor and Howard Hughes Investigator at the RockefellerUniversity. "Aron was a wonderful mentor to his students and to youngercolleagues like me. He taught by example. He set rigorous standards for scientificexcellence and expected us to meet them with the passion he expressed throughouthis career."

Aron Arthur Moscona was born July 4, 1921, in Haifa, Israel. He graduated fromthe Reali High School in Haifa then attended Hebrew University, in Jerusalem,where he earned his PhD in endocrinology-biochemistry in 1950. He spent twoyears as a post-doctoral fellow at the Strangeways Research Laboratory at Cambridge,before joining the faculty at the University of Jerusalem as an associate professorof physiology in 1953. He then spent two years as an investigator at RockefellerUniversity in New York City, before joining the faculty at the University ofChicago as an associate professor of zoology in 1958.

He rose quickly through the ranks at the University, becoming a professor in1960. He co-founded the committee on developmental biology in 1969 and was namedthe Louis Block Professor of Biology in 1974.

A prolific author, he published 261 scientific papers, was co-author of thetext book Introductory Concepts in Developmental Biology, and served as founderand coeditor of the journal Current Topics in Developmental Biology. He servedas president of the International Society of Developmental Biology from 1976to 1980 and as a member of several national advisory panels, including the President'sBiomedical Research Panel in 1975. He was the chair of the board of scientificcounselors of the National Institute of Child Health and Human Development from1982-1986, served on an NIH advisory panel on human fetal tissue transplantationin 1988, and joined the board of governors of Tel Aviv University in 1984, wherehe served until his recent illness.

Moscona won multiple honors for his research, including membership in the NationalAcademy of Sciences in 1977 and in the American Academy of Arts and Sciencesin 1987, as well as its Italian counterpart, the Accademia di Science e Lettere.He received many awards, including the Claude Bernard Medal in ExperimentalMedicine from the European Association for the Study of Diabetes, Japan's AzabuGold Medal and the Alcon Prize in Visual Sciences.

As a post-doctoral fellow at Cambridge, Moscona directed his attention to questionsrelated to the emerging field of developmental biology, especially how differentcell types arose from a fertilized egg cell and organized themselves into tissuesand organs. He developed novel techniques to answer some of those questions.Using the digestive enzyme trypsin, he dissolved tissues into individual cellsthat he kept alive in a flask of culture media, where they could "recognizetheir own kind," as he put it, "sort out and reassemble into tissue-likepatterns."

He constantly revised the approach to study related topics in different tissuetypes--including muscle, skin, liver, pancreas, retina and brain--and to applythem to different life forms, ranging from marine sponges to chickens, snakes,mice and even human tissues.

One of his central findings was that specific cell-surface molecules definedeach cell type, serving as microscopic flags to identify each cell as a liver,kidney or brain cell. These markers, which Moscona labeled "cognins,"(later known as cadherins) enabled the dissociated cells to recognize and connectwith similar cells. He also showed how forming these cell-to-cell connectionscould alter gene expression and that they were necessary for the embryonic cellsto mature.

In the mid-1960s, much of his efforts focused on the mechanisms that controllednerve cell differentiation. One spin-off from this was the development in 1972by Moscona and colleague Beatrice Garber of aggregate neural tissues that couldsurvive for years, proving a new tool for study of the brain. Neuroscientistsat the University, for example, used these neural aggregates, known as "mini-brains,"to study the neurotoxicity of various drugs of abuse.

Moscona's partner in many of these efforts was his wife, Malka, who had alsogrown up in Haifa. Although they attended the same high school, they did notmeet until later, at the Hebrew University in Jerusalem, and married in 1956.A very popular instructor and winner of the University's Quantrell Award forexemplary teaching, Malka Moscona also joined the Chicago faculty in 1958, becomingan associate professor.

"They worked together collaboratively for 40 years, in the same laboratory,carrying out projects together from 1958 until 1974, and were jointly responsiblefor the body of science," said their daughter Anne Moscona, MD, a virologistand infectious disease specialist at Weill Medical College of Cornell Universityin New York City.

Moscona retired in 1992. He and his wife moved to New York, to be near theirdaughter and her family. His wife continued her science outreach and teachingwork there. "Late in life," his daughter Anne said, "he becamevery nurturing." He took his two grandsons to their classes, picked themup from school, took them to the playground, cooked dinners for them, "boughtthem books," she added, "and instilled a love of learning, history,music, art and, of course, science."

Moscona is survived by his wife of 53 years and scientific collaborator, Malka,his daughter Anne, and two grandchildren, Jacob and Ari, all of Manhattan.