Eukaryotic DNA Replication - Polymerisation Flashcards
(11 cards)
Which DNA Polymerase is used to synthesise the leading strand in eukaryotic replication?
DNA Polymerase episilon
Which DNA Polymerase is used to synthesise the lagging strand in eukaryotic replication?
DNA Polymerase delta
What replicative molecule is Proliferating Cell Nuclear Antigen associated with and what is the function?
PCNA is associated with DNA Polymerase and its function is to strengthen the association between the template and polymerase to promote processivity of the polymerase.
What is the significance of specialised proteins acting between helicases and polymerases?
DNA helicases and polymerases must remain in close association with each other at the replication fork so these specialised proteins regulate helices activity ahead of replication to ensure that unwinding and synthesis occur at the same time.
What are the single strand binding (SSB) proteins called in eukaryotic DNA replication?
Replication Protein A (RPA)
What are the replisome factors in eukaryotic replication and and what is their function and which strand are they associated with?
The factors are FPC, Clasping, And1 and RFC. Their function is to regulate the polymerase functions and coordinate DNA synthesis on the lagging strand.
What protein complex unwinds the DNA in eukaryotic replication?
The Cdc45-MCM-GINS complex is a helicase that unwinds the DNA.
What is the DNA Damage/Checkpoint protein complex in eukaryotic cells?
ATR/ATRIP.
How are the Okazaki fragments put together in eukaryotic replication?
The DNA segment of the primer of the previous Okazaki fragment is displaced by DNA polymerase and a flap structure is created. The flap is cleaved by endonucleases and the gap is sealed by DNA ligase I.
How does the short flap pathway work in putting Okazaki fragments together?
DNA polymerase displaces primer to create a short flap. FEN1 will cleve the flap. DNA Ligase I will seal the nick.
How does the long flap pathway work in putting Okazaki fragments together?
DNA polymerase will displace a longer fragment than FEN1 can handle so it dissociates from replication complex initially. RPA will bind the long flap. Dna2 is recruited to shorted the flap. FEN1 comes back to cleave the shortened flap. DNA Ligase I seals the nick.
