Přednáška

lter et al., Proc. Natl. Acad. Sci. USA, (1998) 95:10015 Understan-ding the Relation of Apoptosis, MF and BER Ogg1 -/-
Ape +/-
Xrcc1 +/-
PolB +/- BER efficiency Prevalence of Apoptosis Mutant Frequency Ape +/- Short Patch Long Patch 5’
3’ DNA glycosylase Damaged base AP site 5’
3’ 5’
3’ 5’
3’ 5’
3’ Polb/XRCC1 XRCC1/Lig3 dNTP Deoxy
ribophosphate APE Huamani et al., (2004) WT Apex+/- Apoptosis is Elevated Among MGCs of APE+/- mouse? Huamani et al., (2004) 3 m/o 9 m/o Spontaneous Mutagenesis is Elevated in Spermatogenic Cells of 9-Month-Old Apex+/- Mice Hmmm, to se ale tyka jen zarodečných buněk. Co je nam po nich...Co tak třeba kmenovky...? CCTL-9c/m CCTL-12c CCTL-12m CCTL14c CCTL-14m ... p22 47XX, +17
cp 64 – 114 46xx ... P18 mosaic der.7

p 55 - 111 46xx ... P18 mosaic 47XX, +12 46xx ... P18 mosaic Der 12 46xx Mosaic p 42 - 71 Odděleny v 16 pasáži p 76 - 91 p 61 - 216 malé Déjŕ vu... University of Texas Health Science Center at San Antonio, Cellular & Structural Biology
7703 Floyd Curl Drive
San Antonio
78229 Texas Base and single strand damage relation to double strand breaks Does base/nucleotide damage mediate double strand breaks? Vypadá to, že kmenové buňky budou také postiženy zvýšenou mutagenezou ve vyšším věku
A toto by mohl být princip stárnutí a zvýšeného rizika rakoviny ve vyšším věku There are pathways leading from one lesion to another
But are they biologically relevant and/or important? Relationship between base/nucleotide damage, single strand breaks and double strand breaks Base/nucleotide damage
NER, BER, MR etc. Double strand Break
NHEJ, HR etc Single strand break DNA
Damage IR x x Stochastic Distribution of IR Damage Stochastic distribution of single strand break oxidative damage does not create double strand breaks. DSB formation is independent of SS damage and SSB.
(h) x …up to 50 radicals
from single event x x x x Clustered
damage
(e.g. OxoG) Free Radical Channeling H2O, H2O2 (h) Possible radical reactions in cells, mediating the damage:
Radiolysis of fatty acids
Radiolysis of H2O
Fenton-Haber-Weiss reaction of H2O2 with transition metals BER enzymes (specific glycosylase and APE endonuclease Clustered damage Clustered SSBs x x x DSB Clustered Single Strand Damage Clustered Single Strand Damage Can Lead to Formation of Double Strand Breaks DNA glycosylase Damaged base AP site 5’
3’ 5’
3’ (h) 5’
3’ NO glycosylase Ogg1 -/- Ogg1 KO Mouse as a model for Clustered Damage Ogg1 KO Mouse Example of Response of Ogg1 KO Round Spermatids to IR Kinetics of DSB repair Dr.Ber:
“The surgery was successful, however the patient died” Lichten, Current biology 2001 http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/genetic-analysis/recombination/rec-molecular.html Mechanismus homologní rekombinace Aktivní vytvoření zlomů DNA a tvorba D smyčky
Posun bodu překřížení, syntéza a ligace, tvorba chi struktury Dult progeria

Werner syndrome
Autosomal recessive
DNA helicase involved in HR Sorry, no elixir of life this time…. END