DNA Replication Flashcards
Where are the phosphate groups added in dexoxyribose
At the 3’ end
When does ORC binds to the DNA origin
Late M/early G1 phase
What binds to ORC to start trasncription
cdt1 and cdc6
What do these factors recruit
MCM helicase units
Which factor licenses replication
cdc6
What does it do
brings along cdt1 and MCM helicase
How does the levels of cdc6, cdt1 and geminin vary
cdc6 rises at the end of G1 phase and stays high until M phase, cdt1 increase at the end of M phase (all the way through G1) and geminin levels are high all the time except when cdt1 levels are high
What happens after the MCM complex opens the DNA
DNA primase and DNA pol alpha comes in and the DNA polymerase (DNA epsilon and theta) comes in,.
Topoisomerase loosens up the DNA
What is RPA
Single strands of DNA are held by replication protein A (RPA) to prevent them from joining back
What is the second step in replication
CDK (prolly 4 and 6) p’s MCM, activating it
What happens next
RPA and MCM are the prereplicative complex. ORC goes away
Next
DNA Primase makes about 10 nts, pol alpha adds about another 30 nts, so now DNA e and t can come in and kick out the RNA nts and add DNA nts and bind them together by phosphodiester bonds.
What does the pol e and t need for their activity
PCNA which is a clamp (proliferating cell nuclear agent)
What direction is the DNA read and what direction is the DNA made
Always made 5’ to 3’ direction, read in 3’ to 5’
What kind of coils are introduced by the replciative fork
positive super coils, topo induces negative super coils
