Re: Hormesis in DSB formation and repair

["Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>]

>>That with each DSB the cell statistically moves one step further into 

>>either towards genomic chaos or cell death.



>You're not saying that the authors of this paper are considering misrepair 

>in their measure of "enhanced repair"?



My point was not about enhanced repair. It was instead that a large fraction 

of radiation induced DSBs in mammalian cells, depending on the status of the 

cell (position in cell cycle and other factors that haven't been well 

understood yet), are rejoined in such a way that errors are introduced (due 

to non-homologous end-joining, NHEJ).



If the NHEJ pathway in knocked out a larger fraction of DSBs will be 

rejoined by homologous recombination which - I assume - usually retores the 

original sequence. If however, the damaged DNA section is located in a 

region where the homologous chromosome (originally from the other parent of 

the individual - here used as "backup") carries a critical allele (that 

represents a critical step in the development of a tumor for instance) this 

deficient allele may get full penetrance.



The word "repair" can easily be misunderstood as meaning "correct repair" 

(but it also includes mis-repair). Therefore the word "rejoining" is better 

(I have used the word "repair" in a few publications but have shifted over 

to rejoining in many contexts).



Please add or modify whatever you may find relevant.



My personal comment only,



Bjorn Cedervall





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