VOLUME 12, NUMBER 20 • APRIL 20, 2001

Simpson to Give Friedheim Memorial Lecture

Larry Simpson, a professor of microbiology, immunology and molecular genetics at the UCLA School of Medicine, will present the Ernst A.H. Friedheim Memorial Lecture on Fri., April 27. His topic will be "The Mechanism of Uridine Insertion/Deletion RNA Editing in Trypanosome Mitochondria."

Trypanosomes, or kinetoplastid protozoa, comprise a large group of parasites responsible for a variety of human, animal and plant diseases. They are of intrinsic interest to scientists, because they have evolved fundamentally different cellular pathways than the better- studied organisms, such as bacteria, yeast and mammals.

Larry Simpson is a professor of microbiology, immunology and molecular genetics at the UCLA School of Medicine and an investigator at the Howard Hughes Medical Institute.

Simpson, who is also an investigator at the Howard Hughes Medical Institute, will discuss an unusual property of trypanosome mitochondria, known as RNA editing. In RNA editing, mitochondrial messenger RNAs are modified by the insertion or deletion of uridine residues at specific sites within coding regions, thereby creating open reading frames for the synthesis of proteins.

In 1990, Simpson discovered that the information for this editing is encoded in small guide RNAs, termed gRNAs, which bind to the messenger RNA and mediate the transfer of uridine. His lab has isolated other components of the system as well, and currently is reconstituting the process in vitro as a means of further elucidating editing mechanisms. Simpson’s research interests also include the mechanism by which transfer RNAs–molecules essential for transcription–are imported into trypanosome mitochondria, and the evolution of RNA editing.

A graduate of The Rockefeller University, Simpson received his Ph.D. in molecular parasitology from the laboratory of William Trager in 1967. He earned his B.A. in biology from Princeton University in 1962 and completed his postdoctoral training with Maurice Steinert at the Free University of Brussels in 1969.

In addition to currently serving as a Howard Hughes Medical Institute investigator and professor of microbiology, immunology and molecular genetics at the University of California, Los Angeles, School of Medicine, he also is a member of the Molecular Biology Institute and the Jonsson Cancer Institute at UCLA. Simpson is a Fellow of the American Association for the Advancement of Sciences and a Foreign Member of the Brazilian Academy of Sciences.

He is the author of more than 150 research papers.

Simpson’s talk will begin at 3:45 p.m.in Caspary Auditorium and is preceded by a tea in the Abby Lounge at 3:15 p.m. All are welcome.