"In this study we looked at what nerves are made in a particular part of the brain, the hindbrain," says geneticist Mario Capecchi, professor and co-chair of human genetics at the University of Utah School of Medicine and an investigator with the Howard Hughes Medical Institute (HHMI). "We see that in certain parts of the hindbrain, the embryo makes nerves that innervate the facial muscles, and in another part of the hindbrain, the embryo makes nerves that innervate eye movement."
The findings will be published in the Nov. 1 issue of the journal Development. Capecchi conducted the research with Gary Gaufo, a postdoctoral fellow in human genetics and HHMI research associate, and geneticist Kirk Thomas, formerly of the University of Utah and Howard Hughes Medical Institute and now working at Hydra Biosciences in Boston.
The study used a method developed by Capecchi and for which he has won numerous awards. It is called gene targeting, and involves disabling or "knocking out" various genes in mice to see what goes wrong, thus learning what the genes normally do.
The researchers found that by crippling two genes, mice failed to develop nerves that normally connect to one of six sets of muscles controlling eyeball movements. Disabling other genes made mice develop an extra set of nerve fibers that control facial muscles.
The study deals with what are called homeobox or Hox genes, which are genes that orchestrate the actions of other genes to guide embryo development. The researchers looked specifically at how Hox genes direct development of the hindbrain, o
Contact: Mario Capeccchi
University of Utah Health Sciences Center