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Role of  RecA  in DNA replication Role of  RecA  in DNA replication

Role of RecA in DNA replication - PowerPoint Presentation

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Role of RecA in DNA replication - PPT Presentation

Yadi Zhou 20131205 RecA protein 38 kiloDalton Essential for the repair and maintenance of DNA A RecA structural and functional homolog has been found in every species Homologous protein in ID: 811347

dna reca amp replication reca dna replication amp recombination sos forks response genes single stranded annu rev genet 2003

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Slide1

Role of RecA in DNA replication

Yadi

Zhou

2013.12.05

Slide2

RecA protein38 kiloDaltonEssential for the repair and maintenance of DNAA RecA structural and functional homolog has been found in every speciesHomologous protein in

Homo sapiens

is RAD51

Important enzyme in

homologous

recombination

Induce SOS response

Slide3

Structure

Slide4

RecA filament

RecA-dsDNA

Slide5

Homologous recombination

Slide6

Homologous recombination

Slide7

SOS response

Slide8

E. coli strains deficient in RecA are useful

Potential drug

target

Slide9

Referenceshttp://www.callutheran.edu/BioDev/omm/reca/recamast.htmhttp://en.wikipedia.org/wiki/RecANature Reviews Molecular Cell Biology 8, 127-138 (February 2007)http://www.callutheran.edu/BioDev/omm/reca/recamast.htmNature 453, 463-466(22 May 2008)

Slide10

Thank you!

Slide11

Mechanisms of RecA DNA RepairVivian LesendeDecember 5, 2013BIOS 7200

Slide12

Can arrest replication --- deletions/genomic rearrangements, point mutations, lethalityMany types of lesions can inhibit normal progression of replication forks-UV radiation – cis, syn-cyclobutane pyrimidine dimer (CPD) & pyrimidine-6-4-pyrimidone photoproduct (6-4 PP)DNA Damage

Slide13

RecA functions to recover replication forks in several different ways-acts as transactivator for upregulating over 40 genes (SOS response)-protects single stranded DNA from degradation while replication is arrested-promotes recombination repair

RecA

Functions

Slide14

LexA -- repressor binds to a 20 bp consensus sequence in operator region in DNA-damage inducible genesRecA bound to damaged single stranded DNA causes autocatalytic cleavageIncreases transcription of genes involved in SOS ResponseSOS Response

Slide15

Genes that function to remove lesions and restore replicationuvrA & uvrB -- recognize UV-induced lesionsydjQ (cho) -- incision step for excision repairpolB, dinB

,

umuC

&

umuD

– DNA polymerases Pol II,

PolI

V, Pol V

Genes Involved in SOS Response

Slide16

SOS ResponseCourcelle & Hanawalt

.

Annu

. Rev. Genet. 2003. 37:611-46

Slide17

RecA maintains structure of replication forks until replication resumesAllows for nucleotide excision repair to occurrecA mutants have high sensitivity to UV-light – “rec-less” degradationPrevention of Degradation of Single-Stranded DNA of Replication Forks

Slide18

Prevention of Degradation of Single-Stranded DNA of Replication ForksCourcelle

&

Hanawalt

.

Annu

. Rev. Genet. 2003. 37:611-46

Slide19

“postreplication repair” or “daughter-strand gap repair”RecA promotes recombination as an alternative to excision repair – does not remove lesions from DNATypically only occurs if previous mechanisms have failedRecombination Recovery

Slide20

Recombination RecoveryCourcelle & Hanawalt.

Annu

. Rev. Genet. 2003. 37:611-46

Slide21

J. Courcelle & P. C. Hanawalt. RecA-Dependent Recovery of Arrested DNA Replication Forks. Annu. Rev. Genet. 2003. 37:611-46References