Fusion proteins or
chimeric proteins (literally, made of parts from different sources) are proteins created through the joining of two or more
genes that originally coded for separate proteins. Translation of this
fusion gene results in a single or multiple
polypeptides with functional properties derived from each of the original proteins.
Recombinant fusion proteins are created artificially by
recombinant DNA technology for use in biological research or
therapeutics.
Chimeric or
chimera usually designate hybrid proteins made of
polypeptides having different functions or physico-chemical patterns.
Chimeric mutant proteins occur naturally when a complex
mutation, such as a
chromosomal translocation, tandem duplication, or retrotransposition creates a novel coding sequence containing parts of the coding sequences from two different genes. Naturally occurring fusion proteins are commonly found in cancer cells, where they may function as
oncoproteins. The
bcr-abl fusion protein is a well-known example of an oncogenic fusion protein, and is considered to be the primary oncogenic driver of
chronic myelogenous leukemia.