Confirmation of homozygosity for a single nucleotide substitution mutation in a Cockayne syndrome patient using monoallelic mutation analysis in somatic cell hybrids.
The identification of individuals homozygous for a specific mutation offers advantages for the elucidation of molecular mechanisms of hereditary disease states. Cockayne syndrome is a rare autosomal recessive disorder, the molecular basis of which is complicated by significant genetic and clinical heterogeneity. The genes associated with both genetic complementation groups, CSA and CS-B, have been identified. We have previously identified a number of CSA mutations, including a single base substitution that introduces a stop codon (322Tyr-->Stop) mutation in the C-terminal region for at least one allele of the CSA gene in a severely affected patient. We now present data confirming the existence of homozygosity in this patient using a strategy with general applicability. Somatic cell hybrids were established by fusing patient cells with mouse A9 cells. Screening with chromosome 5 specific polymorphic markers facilitated identification of hybrid clones bearing only one of the distinct CSA alleles. Sequencing of a portion of the human CSA gene in a subset of these hybrids permitted monoallelic mutation analysis and confirmed the presence of the 322Tyr-->Stop mutation in both alleles.
McDaniel
L D
LD
McDermott Center, University of Texas Southwestern Medical Center, Dallas 75235, USA.
Legerski
R
R
Lehmann
A R
AR
Friedberg
E C
EC
Schultz
R A
RA
D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002459:Cell Fusion / Q000235:genetics; D003057:Cockayne Syndrome / Q000235:genetics*; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins; D005347:Fibroblasts / Q000528:radiation effects; D005819:Genetic Markers; D005821:Genetic Techniques; D006720:Homozygote; D006801:Humans; D006822:Hybrid Cells; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D011110:Polymorphism, Genetic; D011506:Proteins / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors; D014466:Ultraviolet Rays
C490652:Ckn1 protein, mouse; D004268:DNA-Binding Proteins; C095472:ERCC8 protein, human; D005819:Genetic Markers; D011506:Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D045643:DNA Repair Enzymes