© 1994 Oxford University Press
research-article |
Correction by the ERCC2 gene of UV sensitivity and repair deficiency phenotype in a subset of trichothiodystrophy cells
Laboratory of Molecular Genetics UPR42 CNRS IFC H01, BP no. 8, 94801 Villejuif, France
1Department of Cell Biology and Genetics, Erasmus University PO Box 1738, Rotterdam, The Netherlands
2consiglio Nazionale delle Ricerche, Istituto di Genetica Biochimica ed Evoluzionistica Via Abbiategrasso 207, 27100 Pavia, Italy
3MRC Cell Mutation Unit, University of Sussex Falmer, Brighton BN1 9RR, UK
4Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory PO Box 5507, Livermore, CA 94550, USA
5To whom correspondence should be addressed
Trichothiodystrophy (TTD) is a rare genetic disease with heterogeneous clinical features associated with specific deficiencies in nucleotide excision repair. Patients have brittle hair due to a reduced content of cysteine-rich matrix proteins. About 50% of the cases reported in the literature are photosensitive. In these patients an altered cellular response to UV, due to a specific deficiency in nucleotide excision repair, has been observed. The majority of repairdefective TTD patients have been assigned by complementation analysis to group D of xeroderma pigmentosum (XP). Recently, the human excision repair gene ERCC2 has been shown to correct the UV sensitivity of XP-D fibroblasts. In this work we describe the effect of ERCC2 on the DNA repair deficient phenotype of XP-D and on two repair-defective TTD cell strains (TTD1VI and TTD2VI) assigned by complementation analysis to group D of XP. ERCC2 cDNA, cloned into a mammalian expression vector, was introduced into TTD and XP fibroblasts via DNA-mediated transfection or microneedle injection. UV sensitivity and cellular DNA repair properties, including unscheduled DNA synthesis and reactivation of a UVirradiated plasmid containing the chloramphenicol acetyltransferase reporter gene (pRSVCat), were corrected to wild-type levels in both TTD and XP-D cells. These data show that a functional ERCC2 gene is sufficient to reestablish a wild-type DNA repair phenotype in TTD1VI and TTD2VI cells, confirming the genetic relationship between TTD and XP-D. Furthermore, our findings suggest that mutations at the ERCC2 locus are responsible for causing a similar phenotype in TTD and XP-D cells in response to UV irradiation, but produce quite different clinical symptorns.