DNA replication
Central dogma of molecular
biology
1.the basic principle of DNA
replication
(1) Semiconservative
replication
a. concept
b. evidence
c. conclusion
(2) Semidiscontinuous replication
* The synthesis direction of
DNA polymerase
* leading strand & lagging
strand
* Okazaki fragment
(3) RNA primer
* the synthesis
* the function
(4) fidelity
2. Enzymes & proteins cooperate
in the DNA replication
(1) E.coli DNA polymerase I
(Kornberg enzyme,DNA-Directed
DNA polymerase,DDDP,pol I )
* The principle materials for pol I
# four dNTP
# Mg 2+
# RNA primer or DNA single
strand possessed 3’-OH
# DNA template
* Multiple function of pol I
Klenow fragment-------
(large fragment)
DNA polymerase activity,
3’-5’ exonuclease activitysmall fragment-------
5’-3’ exonuclease activity
5’ 3’ 3’ 5’ exonuclease exonuclease DNA polymerase activity activity activity
Small fragment large fragment (Klenow fragment)
pol I
Proofreading
* the principle materials for pol II
& pol III
# four dNTP
# Mg 2+
# RNA primer or DNA single
strand possessed 3’-OH
# DNA template
* the characteristics of pol II & pol III
pol II---mostly concerned with
proofreading & DNA repair
pol III---- indispensable for DNA
replication,the highest rate
of chain elongation and
processive
(2) DNA polymerase in eukaryocyte polymerase : gap filling & synthesis of lagging
strand
: DNA proofreading & repair
: DNA repair
: mitochondria DNA synthesis
: processive,leading strand synthesis,
need the assistance of PCNA
(3) helicase & gyrase
a. helicase
* function
* require
b. single strand binding protein
(SSB) ,helix disabling
protein,HDP
* function
c. topoisomerase I
* function
d. topoisomerase II, gyrase
* function
(4) Primosome
(5) DNA ligase
* function
* require
* process
* characteristics
* usage
3.procedure of DNA replication
(1) the initiation of the
replication
* the origin of replication ----
The special structure
(ori C)
* the process of initiation
formation of replication fork
( replication bubbles)
* how to deal with synthesis
direct ?
(3) the termination of the
replication
(2) the elongation of the
replication
*Removes primers---- pol I
small fragment
* fills the gap with dNTP----- pol I
large fragment
(Klenow fragment)
* ligation----DNAligase
4. Summarize of DNA replication
a.identification of the origin of
replication
b.unwinding (denature)of ds DNA to
provide ssDNA
c. formation of replication fork
d.initiation of DNA synthesis & elongation
e. formation of replication bubbles with
ligation of the newly synthesized DNA
segment
f. Reconstitution of chromatin DNA
5.Telomere & telomerase
(1) telomere
*concept
*structure
* function
(2) The function & molecular
components of telomerase
* function
* components (RNP)
* mechanism
• Telomerase & carcinoma
5.DNA damage & repair
(1) the basic of repair
(2)the causes of DNA damage
*remove purine by heat &
acid
• ionizing radiation
• ultraviolet ray
• chemical agents
(3) The type of DNA damage
(4)Mechanism of DNA repair
* photo repair
* excision repair
significant (correct large defects)
* base excision repair
a.process
• Characteristics
• summarize
a. the enzyme uracil DNA
glycosylase removes the uracil
created by spontaneous
deamination of cytosine
b. an endonuclease cuts the
backbone near the defect
c. an endonuclease removes a
few bases
d. the defect is filled in by the
action of a repair polymerase
( pol I )
e. The strand is rejoined
by ligase
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