Radiation effects(toxicity)2

[HWADE@aol.com]

The human gene(s) that exist in every human cell and repair damage
caused by ionizing radation have first been cloned, and now something has
been learned about the details of the repair mechanism.
Some references to these studies are:

1. Caldecott KW; McKeown CK; Tucker JD; Ljungquist S; Thompson LH.
An interaction between the mammalian DNA repair protein XRCC1 and 
DNA ligase III.
Molecular and Cellular Biology, 1994 Jan, 14(1):68-76.

2. Sung P; Bailly V; Weber C; Thompson LH; Prakash L; Prakash S.
Human xeroderma pigmentosum group D gene encodes a DNA helicase.
Nature, 1993 Oct 28, 365(6449):852-5.

3. Liu P; Siciliano J; White B; Legerski R; Callen D; Reeders S;
Siciliano MJ; Thompson LH.
Regional mapping of human DNA excision repair gene ERCC4 to 
chromosome
Mutagenesis, 1993 May, 8(3):199-205.

4. Caldecott KW; Tucker JD; Thompson LH.
Construction of human XRCC1 minigenes that fully correct the CHO DNA
repair mutant EM9.
Nucleic Acids Research, 1992 Sep 11, 20(17):4575-9.

5. Yoo H; Li L; Sacks PG; Thompson LH; Becker FF; Chan JY.
Alterations in expression and structure of the DNA repair gene XRCC1.
Biochemical and Biophysical Research Communications, 1992 Jul 31,
186(2):900-10.

6. Dunphy EJ; Beckett MA; Thompson LH; Weichselbaum RR.
Expression of the polymorphic human DNA repair gene XRCC1 does not
correlate with radiosensitivity in the cells of human head and neck tumor
cell lines.
Radiation Research, 1992 May, 130(2):166-70.

7. Thompson LH; Wu RW; Felton JS.
Introduction of cytochrome P450IA2 metabolic capability into cell lines
genetically matched for DNA repair proficiency/deficiency.
Proceedings of the National Academy of Sciences of the United States of
America, 1991 May 1, 88(9):3827-31.

8. Thompson LH.
Properties and applications of human DNA repair genes.
Mutation Research, 1991 Apr, 247(2):213-9.

9. Tucker JD; Jones NJ; Allen NA; Minkler JL; Thompson LH;
Carrano AV.
Cytogenetic characterization of the ionizing radiation-sensitive Chinese
hamster mutant irs1.
Mutation Research, 1991 Mar, 254(2):143-52.

10. Thompson LH; Brookman KW; Jones NJ; Allen SA; Carrano AV.
Molecular cloning of the human XRCC1 gene, which corrects defective DNA
strand break repair and sister chromatid exchange.
Molecular and Cellular Biology, 1990 Dec, 10(12):6160-71.

11. Olson E; Edmondson D; Wright WE; Lin VK; Guenet JL; Simon-
Chazottes D; Thompson LH; Stallings RL; Schroeder WT; Duvic M; et al.
Myogenin is in an evolutionarily conserved linkage group on human
chromosome 1q31-q41 and unlinked to other mapped muscle
regulatory factor genes.
Genomics, 1990 Nov, 8(3):427-34.

12. Troelstra C; Odijk H; de Wit J; Westerveld A; Thompson LH;
Bootsma D; Hoeijmakers JH.
Molecular cloning of the human DNA excision repair gene ERCC-6.
Molecular and Cellular Biology, 1990 Nov, 10(11):5806-13.

13. Weber CA; Salazar EP; Stewart SA; Thompson LH.
ERCC2: cDNA cloning and molecular characterization of a human 
nucleotide excision repair gene with high homology to yeast RAD3.
Embo Journal, 1990 May, 9(5):1437-47.

14. Regan JD; Thompson LH; Carrier WL; Weber CA; Francis AA; 
Zdzienicka MZ.
Cyclobutane-pyrimidine dimer excision in UV-sensitive CHO mutants and 
the effect of the human ERCC2 repair gene.
Mutation Research, 1990 May, 235(3):157-63.

I speculate that:
If it should be that this repair is a rate function, then whenever the rate
of 
damage is less than the rate of repair, the total dose can be essentially 
neglected.  Keeping the rate of exposure below the rate of repair would be
all that mattered.

Best wishes to all,
Wade Patterson
J. Muckerheide please copy