It appears to me that most plasmid DNA entering a human cell gets degraded (perhaps rapidly but not sure about the rate) and only a small portion find their way into the nucleus. What exactly happens in the cytoplasm? Has anyone carefully investigated this? Are there tricks to reduce such degradation in cytoplasm? Please share your experiences.
During chromosome replication, the enzymes that duplicate DNA cannot continue their duplication all the way to the end of a chromosome (DNA Polymerases can only synthesize 5' to 3'), so in each duplication the end of the chromosome is shortened (this is because the synthesis of Okazaki fragments requires RNA primers attaching ahead on the lagging strand). Telomerases are part of a distinct subgroup of RNA-dependent polymerases responsible for catalyzing the addition of nucleotides in a TTAGGG sequence to the ends of a chromosome’s telomeres.
Thats how some transfection reagents work, for example turbofect. Polymer-DNA complex is uptaken by endosomes/lysosomes rich in hydrolytic enzymes. Thus it would be degraded there. However polymer due to "proton-sponge" effect buffers acidic compartment, causes its swelling and rupture. DNA-polymer complex safely travels to nucleus.
- Badges
- Science topic