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