Nucleases (In DNA Extraction)

[Melstmu2010]

Where are nucleases located? In DNA Extraction, how are they activated? Extraction allows nucleases in solution. Why should we prevent this?

[Argentum]

My understanding is that within the cell, nucleases tend to be localized to the cytoplasm. They typically function in degradation of mRNA transcripts. This provides a control on expression of that mRNA (if they were not degraded, then the same transcript would be continuously translated yielding too much of that protein).

It isn't that they are activated during DNA extraction procedures. The issue is that the nuclear DNA is usually protected from degradation by nucleases by the nuclear envelope. It would be quite detrimental if they degraded the DNA code of the cells on a regular basis. During extraction, the nuclear membrane is lysed in order to allow the DNA to be released into the solution. If you do not stop the action of the nucleases, they will cleave the DNA that you are looking to extract, which has some obvious negative implications for some intended uses of the DNA.