H. Robert Horvitz identified the genes that play a significant role in programmed cell death and amyotrophic lateral sclerosis (ALS); he also discovered a new receptor that responds to serotonin. His pioneering research was performed on the nematode Caenorhabditis elegans.
C.elegans is a translucent worm about 1 millimeter long. Its genetic similarity to humans has made the nematode a focus of scientific study. In 1965, Dr. Sydney Brennan was the first to decide that the tiny creature was an ideal model for the study of the genetic code because it has far fewer genes than a human being, and yet its genetic structure is remarkably similar to a human's. Within two decades, biologists around the world were studying the worm and its 1090 cells. Indeed, work on sequencing its genome assisted molecular biologists studying the human genome. Moreover, medical biologists often collaborate with worm biologists, noting, for example, that the genes in C.elegans are similar to those defective genes in humans that cause Alzheimer's and colon cancer.
Horvitz's research on C.elegans led to an important discovery in 1991, when Horvitz identified the process of programmed cell death, or apoptosis. Understanding apoptosis is important because human diseases, including some cancers and neurodegenerative diseases, are related to the misregulation of apoptosis. Horvitz has identified the roles of several genes in the process of apoptosis in C.elegans, and some of these genes are similar to those in human apoptosis. In 2000, Horvitz and his research team announced that they had discovered a protein that signals the process of programmed cell death. The finding will possibly enable scientists to develop drugs to prevent cell death in different disabling conditions, such as Alzheimer's.
Leading a team of scientists in 1993, Horvitz identified the gene responsible for amyotrophic lateral sclerosis, or Lou Gehrig's disease (so-named after the New York Yankees ballplayer who died of ALS in 1941 at the age of 38). ALS is a fatal disorder of the nervous system characterized by increasing stiffness and total paralysis. Horvitz and his team found that the defective superoxide gene, which produces an enzyme called superoxide dismutase, is responsible for ALS. Because it is mutated, superoxide dismutase (SOD) in ALS patients does not deactivate free radicals, metabolic byproducts long linked to various diseases, including Alzheimer's and Parkinson's. Horvitz's discovery of SOD mutations in ALS victims is an important first step toward finding a cure for this and other similar conditions.
Horvitz announced in November 2000, in an article co-authored by Horvitz and two others, the discovery of a new type of fast receptor in C. elegans. The researchers found a gene that encodes an inhibitory receptor, while previously the only fast receptor known for serotonin was an excitatory one. The finding will spur further research to locate a similar inhibitory serotonin receptor in humans and thus, to develop a new pharmalogoical approach to treating the several conditions caused by neurotranmitter dysregulation, including depression, anxiety, and schizophrenia.
Horvitz completed his undergraduate work at Massachusetts Institute of Technology (MIT) in 1968, and received his Master's degree (1972) and Ph.D. (1974) in biology from Harvard University. After postdoctoral research in Cambridge, England, he joined the faculty of MIT in 1978. The recipient of numerous awards and honors, Professor Horvitz is a member of the National Academy of Sciences and is currently Professor of Biology and Investigator, Howard Hughes Medical Institute, MIT.