Identification of nucleotide-excision-repair genes on human chromosomes 2 and 13 by functional complementation in hamster-human hybrids

Abstract

The CHO UV-sensitive mutants UV24 and UV135 (complementation groups 3 and 5, respectively) are defective in nucleotide excision repair. After fusing each mutant with human lymphocytes, resistant hybrid clones showing genetic complementation were isolated by repeated exposure to UV radiation. Using a combination of isozyme markers, DNA probes, and cytogenetic methods to analyze the primary hybrids and their subclones, correction of the repair defect was shown to be correlated with the presence of a specific human chromosome in each case. Chromosome 2 corrected UV24, and the gene responsible was designated ERCC3. Line UV135 was corrected by human chromosome 13 and the gene designated ERCC5. The UV-sensitive mouse cell line, Q31, was shown not to complement UV135 and thus appears to be mutated in the same genetic locus (homologous to ERCC5) as UV135. Breakage of complementing chromosomes with retention of the genes correcting repair defects allowed the following provisional assignments: regional localization of ERCC5 to 13q14-q34, exclusion of ERCC3 from the region of chromosome 2 distal to p23, and relief of the ambiguity of ACP1 assignment (2p23 or 2p25) to 2p23 proximal to MDH1.

Report of the committee on the genetic constitution of chromosome 2

“…Additional data have confirmed the assignment of a liver specific oncogene to chromosome 2, with a regional localization of q l4 (Tokino et al, 1988). The finding that the oncogene REL migrates with the IGKC gene in a translocation narrows the localization for REL to p i2 -p l3 (Brownell et al, 1988).…”

“…The human gene ERCC3, one of a family of genes responsible for excision repair of DNA, was localized to chromosome 2pl2-qter using somatic cell hybrids (Thompson et al, 1987). Cloning of the gene has confirmed this assignment and narrowed it to 2q21 by in situ hybridization (I Ioeijmakers et al,HGM10).…”

Complementation of a DNA repair defect in xeroderma pigmentosum cells by transfer of human chromosome 9.

“…These observations indicate that repair gene(s) for different complementation groups may be present on different chromosomes. This is also apparent from the fact that different human chromosomes complement the repair defects in CHO mutants belonging to different groups (21). Since chromosomes 9 and 15 have not, as yet, been tested against other complementation groups, the presence of additional repair gene(s) on these chromosomes cannot be ruled out.…”

Report of the committee on the genetic constitution of chromosomes 1 and 2

“…Thompson et al (1987) and Siciliano et al (HGM9) have assigned a human DNA repair gene of the CHO excision repair complementation group 3 (ERCC3) to 2p23-qter with somatic cell hybrids.…”