Gd. Frederick et al., STRUCTURAL AND MUTATIONAL ANALYSIS OF THE XERODERMA-PIGMENTOSUM GROUP-D (XPD) GENE, Human molecular genetics, 3(10), 1994, pp. 1783-1788
Individuals affected by the autosomal recessive disease xeroderma pigm
entosum (XP) are acutely sensitive to sunlight and predisposed to skin
cancer on exposed areas. Cells cultured from XP patients are both UV
sensitive and defective in the nucleotide excision repair of damaged D
NA. These cellular phenotypes are amenable to experimental strategies
employing complementation, an approach previously used to demonstrate
the correction of XP-D phenotypes following the introduction of the XP
D (ERCC2) gene. In the present study, we have characterized the genomi
c organization of the XPD (ERCC2) gene and found it to be comprised of
23 exons. These data were helpful in evaluating the functional integr
ity of alleles in two XP-D cell lines. In cell line GM436 a C-->G tran
sversion was found at nucleotide position 1411 in the XPD (ERCC2) cDNA
, a change expected to result in a Leu461Val substitution. Cell line X
P67MA carries a C-->T transition in genomic DNA at nucleotide position
2176 in exon 22, introducing the termination codon TAG at amino acid
726. The latter would be expected to produce a protein truncated by 34
amino acids. Although expression of the normal XPD cDNA could be show
n to correct the UV sensitivity phenotype in XP-D cells, cDNA construc
ts bearing either of the two mutations failed to yield complementation
. These results confirm the role of ERCC2 in XP-D and illustrate the p
ower of utilizing cellular phenotypes to evaluate the significance of
single nucleotide substitutions.