Microinjection
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Microinjection refers to the process of using a very fine needle to insert substances at a microscopic or borderline macroscopic level into a single living cell. It is a simple mechanical process in which a needle roughly 0.5 to 5 micrometers in diameter penetrates the cell membrane and/or the nuclear envelope. The desired contents are then injected into the desired sub-cellular compartment and the needle is removed. Microinjection is normally performed under a specialized optical microscope setup called a micromanipulator. The process is frequently used as a vector in genetic engineering and transgenetics to insert genetic material into a single cell. Microinjection can also be used in the cloning of organisms, and in the study of cell biology and viruses.
[edit] Examples
- Scientists can create simple transgenic organisms by injecting genes into the testicle of a nematode at a point where the cells that will become its sperm are undergoing meiosis. Since the developing gametes share a common cytoplasm, all of the nematode's gametes will carry a foreign gene as the result of a single injection.
- Microinjection is used as a vector in transgenic plant production.
- Microinjection of genes into fertilized eggs is a common vector used in the production of higher forms of transgenic animals.
- Microinjection of a gene knockdown reagent such as a Morpholino oligo into eggs or early zygotes is commonly used to probe the function of a gene during development of embryos.
