Abstract
In addition to xeroderma pigmentosum (XP), mutations in the human XPG gene cause early onset of Cockayne syndrome (CS) in some patients. CS causative mutations in such patients all produce truncated XPG proteins. To investigate the notion that the CS phenotype in XPG/CS patients results from C-terminal truncations, we constructed mutants with C-terminal truncations in mouse XPG (Xpg) (D811 residue to stop codon, XpgD811stop and deletion of exon 15, Xpgdeltaex15). In XpgD811stop and Xpgdeltaex15 mutations, the last 360 and 183 amino acids of the protein were deleted, respectively. The XpgD811stop homozygous mice exhibited growth retardation and short life span, but the Xpgdeltaex15 homozygous mice exhibited normal growth, indicating that the deletion of the last 360 amino acids causes CS phenotype but the deletion of the last 183 amino acids does not. Thus, the C-terminal truncation of the Xpg protein does not always cause CS phenotype. [J Radiat Res 44:405 (2003)]
