文档介绍：DNA replication
DNA replication is semi-conservative
DNA polymerases
Replication origins
Assembly of the replication fork
Further readings :
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1 ADN 2 ADN
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DNA replication is semi-conservative
M. Meselson & P Stahl Proc. Nat. Ac. Sci. 1958
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The cell cycle
Gap 1
DNA Synthesis
Mitosis
Gap 2
In the resting state (G0), cells do not divide
G0
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DNA synthesis is catalyzed by DNA-dependent DNA polymerases
dNTP
template strand
strand to be synthesized
DNA polymerization takes place in the 5’ to 3’ direction
DNA polymerase requires a template and a primer
dATP
dTTP
dCTP
dGTP
GGG
DNA polymerase
nucleotides
GGATC
template
primer
5’
5’
PPi
PPi
PPi
PPi
PPi
PPi
Stryer et al. Biochemistry, Freeman Edt
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DNA replication is catalyzed by a DNA-dependant DNA polymerase in the 5 ’ to 3 ’ direction starting at double strand DNA or at a DNA-RNA hybrid
A primase synthesize a RNA primer to initiate replication
DNA polymerases are processive : processivity is the number of phosphodiester bonds that a single enzyme is able to catalyze before dissocation
DNA replication requires a primase to start
dNTP
template strand
strand to be synthesized
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Okazaki fragments
RNA primase
Leading and lagging strands
Size of Okasaki fragments : eukaryotes 200 bp
Alberts et al. MBOC, Garland Edt
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5’
3’
dNTP
RNA primer
5’
3’
NTP
primase
Replication fork
DNAPol d
DNA helicase
DNA helicase
On the « leading strand », DNA is continuously synthesized
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5’
3’
RNA primer
dNTP
RNA primer
5’
3’
NTP
DNAPol a primase
5’
3’
dNTP
RNA primer
ligase
5’
3’
RNA primer
RNAse and DNAPol e
Replication fork
DNAPol e
DNA helicase
DNA helicase
DNA helicase
DNA helicase
On the « lagging strand », DNA is synthesized discontinuously
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The core of the eukaryote plex
Movies (Molecules plexes) and (Cell functions) Mol. Biol. Cell
Linda B. Bloom, University of Florida
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