A GGCAGG motif in minisatellites affecting their germline instability.
Mouse and human genomes contain hypervariable DNA regions consisting of tandem repeats of a short sequence referred to as minisatellites. This variation is thought to arise through processes such as unequal crossover or replication slippage. A mo-1 minisatellite probe comprising a 14-base pair repeat sequence reveals many polymorphic fragments even in DNA of BALB/c sublines. Oligonucleotide probes with single base substitution in the mo-1 have been synthesized and used for assessing sequence involved in generation of polymorphisms. The results indicate that the loci containing mo-1 homologues with mutation in the GGCAGG sequence are monomorphic despite the other mutants showing polymorphism. Reciprocally, locus-specific polymorphic clones, Pc-1 and Pc-2, have been isolated with hybridization to mo-1, and both are shown to contain repeated sequence comprising the GGCAGG sequence. They reveal high mutation rates of 8.8% and 3.3% per gamete, respectively. These results strongly suggest that the motif contributes to the germline instability of minisatellites.
1st Department of Biochemistry, Niigata University School of Medicine, Japan.
K
K
Mitani
Y
Y
Takahashi
R
R
Kominami
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D003433:Crosses, Genetic; D015342:DNA Probes; D004276:DNA, Satellite / Q000235:genetics*; D014644:Genetic Variation; D015698:Genomic Library; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid
D015342:DNA Probes; D004276:DNA, Satellite; D015345:Oligonucleotide Probes