Chimeraplasty

A method of gene therapy based upon the use of a molecule called a chimeraplast, a synthetic blend of DNA and the related molecule RNA, to trick the patient's own cells to remedy a gene defect. Chimeraplasts are made to match the patient's sequence of base pairs (the molecular building blocks of DNA), except in one area, the area of the mutation (the change) that is responsible for the gene defect. There, the chimeraplasts have the correct sequence of base pairs in the DNA. The chimeraplasts are designed to attach to the patient's DNA and activate the DNA repair system, a system that cells normally use to correct mistakes they make in replicating their DNA. The patient's DNA repair system is tricked into treating the chimeraplast as the correct version of the DNA and changing the patient's gene to match the chimeraplast, thus correcting the mutation. The term "chimeraplast" derives from the legendary monster made up of incongruous parts. In Greek mythology, the Chimera was an awesome fire-breathing monster with the head of a lion, the body of a goat, and the tail of a serpent. In medicine, a person who is composed of two genetically distinct types of cells is called a chimera. This may be due to the fusion of two embryos at a very early (blastula) stage. More commonly today, the formation of a chimera is due to transplantation. When bone marrow from one person is used to reconstitute the bone marrow of an irradiated recipient, the recipient becomes a chimera. Here in gene therapy, the chimera is a molecule that does not exist in nature, that is part DNA, part RNA, a molecule of incongruous parts, the chimeraplast.