When the cDNA is formed, the copy integrates into the host cell’s DNA.
Reverse transcriptase is a type of enzyme found in a class of viruses called retroviruses, which include HIV, hepatitis B virus, and some cancer-causing viruses. Retroviruses have RNA rather than DNA as their genetic code, and they can do something most other cells can’t: they can carry out the process of reverse transcription. In other words, they can make DNA from RNA. Reverse transcriptase, as its name suggests, is involved in this process.
With the advent of genetic engineering, human insulin can be produced.
In most cells, DNA carries genetic information. During transcription, DNA molecules are encoded into RNA molecules. These RNA molecules are then used in the cytoplasm of the cell to create proteins during the translation process. Proteins determine what activities cells carry out as they form enzymes and these molecules.
All viruses are parasites that live off their host cells. Most consist only of their genetic code, while some also contain an enzyme, such as retroviruses and reverse transcriptase. To reproduce, viruses must infect a host and then use the host’s cells to pass on their genes. There are several different ways for viruses to reproduce, including the use of reverse transcriptase by retroviruses.
Reverse transcriptase is found in the hepatitis B virus.
When retroviruses infect a host, they generally enter the host cell entirely, losing their protective coat in the process. Once in the host cell, reverse transcriptase carries out the reverse transcription process, making a DNA copy of the virus’s RNA chromosome. This DNA is called cDNA because it is a complementary strand of DNA to RNA.
Once the cDNA is formed, the copy integrates into the host cell’s DNA. Often the cDNA and the genes it contains become a permanent addition to the host’s DNA. The cDNA is now copied, transcribed, and translated with the rest of the DNA by host cell enzymes during regular DNA replication, transcription, and translation. In this way, the virus is able to create other copies of itself and its enzyme, which are then expelled from the cell and can further invade other cells.
Reverse transcriptase is a type of enzyme found in retroviruses such as HIV.
Reverse transcriptase was discovered in 1970 and has played an important role in genetic engineering ever since. This enzyme was isolated from the virus cells and then used to make copies of DNA from different cells. An example of how reverse transcriptase has been used is to duplicate the DNA that encodes a specific protein in a specific organ; insulin is an example.
At one time, diabetics had to inject insulin collected from horses or pigs.
In the old days, diabetics had to use insulin from horses or pigs for their injections. With the advent of genetic engineering, human insulin can now be produced. First, the messenger RNA, or mRNA, that carries the instructions for making insulin, is isolated from the cells of the pancreas that make insulin. Reverse transcriptase adds to mRNA so it can make copies of DNA or cDNA. The cDNA now carries the genes for insulin production and can be used to make large amounts for those who need it.