What are the different types of DNA repair?
At least five major DNA repair pathways—base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR) and non-homologous end joining (NHEJ)—are active throughout different stages of the cell cycle, allowing the cells to repair the DNA damage.
What are the DNA repair systems that have evolved to Recognise DNA damage?
In cancer, downregulation is observed across all DNA damage response mechanisms (base excision repair (BER), nucleotide excision repair (NER), DNA mismatch repair (MMR), homologous recombination repair (HR), non-homologous end joining (NHEJ) and translesion DNA synthesis (TLS).
How does DNA damage lead to mutation?
When DNA carrying a damaged base is replicated, an incorrect base can often be inserted opposite the site of the damaged base in the complementary strand, and this can become a mutation in the next round of replication. Also DNA double-strand breaks may be repaired by an inaccurate repair process leading to mutations.
What are MMR genes?
MMR Genes and Colon Cancer Fortunately, our DNA includes genes that act as repair tools that correct the mistakes made during cell replication. These are called Mismatch Repair (MMR) Genes. MMR genes create a system for recognizing and repairing mistakes that arise during DNA replication.
Which 3 items are required for DNA replication?
Most organisms, including mammals, use bi-directional replication. There are four basic components required to initiate and propagate DNA synthesis. They are: substrates, template, primer and enzymes.
Can DNA damage be reversed?
Most damage to DNA is repaired by removal of the damaged bases followed by resynthesis of the excised region. Some lesions in DNA, however, can be repaired by direct reversal of the damage, which may be a more efficient way of dealing with specific types of DNA damage that occur frequently.
What are 3 possible outcomes when a mutation occurs?
The result of a mutation, a change in the DNA sequence. The effects of mutations can vary widely, from being beneficial, to having no effect, to having lethal consequences, and every possibility in between.
