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Note for: Cooperative Roles of Vertebrate Fbh1 and Blm DNA Helicases in Avoidance of Crossovers during Recombination Initiated by Replication Fork Collapse (doi: 10.1128/MCB.02043-06) Fbh1 (F-box DNA helicase 1) -- treating with the DNA damaging agents; no prominent phenotype, contradict with yeast -- there might be the compensate pw in DT40. FBH(-/-) phenotype in DT40; 1.increase sister chromatid exchange 2.formation of radial structures 3.prevent extensive strand exchange during HR 4.work with Bloom helicase - controling recombination-mediated DSB repair at replication block 5.work with Bloom helicase - reduce frequency of crossover Two major pw to release the replication block; 1. TLS -- using TLS polymerase, synthesis directly across the DNA damage 2. HR -- transient template switch from the damage to newly synthesized daughter strands There has been proposed that db holliday junctions are dissolved by concerted action of RecQ helicase, Blm and Topo-IIIalpha R...

Note for: RAD18 and RAD54 cooperatively contribute to maintenance of genomic stability in vertebrate cells (doi: 10.1093/emboj/cdf534) Major pathway for post-replcational DNA damage; 1. TLS 2. HR Rad18- conserved from lower eukaryotes to vertebrates. double KO, synthetic lethal --> ach has nearly normal kinetic (in term of proliferation). Gap in this study; no one study the role of TLS in maintenance of chromosomal DNA. In yeast, S. cerevisiae; RAD6/RAD18 epistasis group (all in; 1. RAD6(UBC2) 2. RAD18 3. REV1 4. REV3 5. REV7 Rad6 -- E2 conjugating enzyme Rad18 -- has the DNA binding domain it is proposed that Rad18 recruited Rad6 and transferring Ub to the targeted proteins. Another gap --> so far, the targeted for Rad18+Rad6 is still unk, but it has been proposed that it could bind to DNA polymerase that play activity in TLS. Mammals, 2 homologs of RAD6 --> HR6A and HR6B 1 homolog RAD18 --> RAD18 AA comparison; ...

Note for: Homologous recombination and non-homologous end-joining pathways of DNA double-strand break repair have overlapping roles in the maintenance of chromosomal integrity in vertebrate cells (doi:  10.1093/emboj/17.18.5497) Main points of this paper; 1. investigate two proteins; Ku70 and Rad54 2. each responsible for DSB and complement to each other. 3. both repair pw. play role in genetic maintenance DSB -- in lower organisms has been majorly fixed by HR. But in the higher eukaryote, ike in veterbrate - favour NHEJ to fix the DSB (my guess would be the cell is not divided anymore) 3 components important for NHEJ; 1.DNA-PK 2.XRCC4 3.DNA ligase IV Advantage of DT40; 1. high homologous recombination - easy to generate knockout 2.stable phenotype -easy to compare phenotype of the effect genes Reason of this study; no one studies these two genes (KU70 and Rad54) on DSB repair in higher eukaryote except in yeast. In yeast, HR is much pre...

It is very old paper though - Note for: Reduced X-Ray Resistance and Homologous Recombination Frequencies in a RAD54 (-/-) Mutant of the Chicken DT40 Cell Line (doi: 10.1016/S0092-8674(00)80198-1 ) Done in S. cerevisiae before and want to investigate in vertebrate -- therefore, DT40 is chosen. 1. Rad54(-/-) was generated 2. Testing this KO - found out that sensitive to radiation, Ig gene conversion reduce, lower targeted integration 3. Complementary testing with human cDNA -- regain radio-resistant and targeted integration **first report on DBS in vertebrate cells. In yeast model study --> found out that either Rad51,Rad52 and Rad54 mutants --> DSB stay long after injure by X-ray Targeted integration in mammal is hard due to the majority of DSB repair occurs through NHEJ (my guess would be less S-phase period and no check point during intra-S? --> need to check which mammalian cell lines were used) Vertebrate cell line model: DT40 is a good mode...