 shown by UCSF investigator Tom Kornberg, PhD, of the UCSF Cardiovascular Research Institute, to mediate cell-cell signaling in the fruit fly Drosophila. This earlier research also observed similar structures in chick embryos, work that has now been extended by Barna and her colleagues.
The researchers got an unprecedented look at previously invisible extensions of cells that form tube-like projections. These specialized filopodia pass along critical instructions essential for the formation of the limbs and digits of developing embryos.
The researchers found that the newly identified, nearly invisible finger-like projections burrow through tightly packed tissue in developing chick and mouse embryos for several cell-lengths. Once contact between cells through these structures has been made, signaling molecules can be delivered directly from one cell to another.
The researchers believe that cells use specialized filopodia as a means of targeted delivery of key signaling molecules in the limb to instruct formation of, say, a thumb versus a pinky finger. If that communication mechanism breaks down, then malformations occur – such as too many or too few fingers or toes.
The wider implication for this research is that similar mechanisms might underlie developmental pattern formation in other organs such as the brain. If so, scientists can learn how and why congenital anomalies occur in other parts of the body.
Lead author Timothy Sanders, MD, PhD, now of Children’s Hospital of Pittsburgh, was a fellow and faculty member in the Division of Neonatology in the Department of Pediatrics at UCSF Benioff Children’s Hospital while conducting the research. He was supported by a National Institute of Child Health and Development training program award (grant T32HD071860), which was critical for the report of these studies. Esther Llagostera, a UCSF post doctoral fellow, is co-author.
The research was supported by the Spanish Ministry of Education and Science, the Program for Breakthrough Biomedical Research at UCSF, the March of Dimes Basil O'Connor Scholar Research Award and the National Institute of Arthritis and Musculoskeletal and Skin Disease (grant R21AR062262).