Figure 1.

Reduced cytosine methylation of centromeric repeats in Bor-4. (A) Genomic DNA samples from the indicated genotypes were digested with the isoschizomers HpaII or MspI, and DNA blot hybridization with a 180-bp centromere repeat probe (CEN) was performed. (B) The filter shown in A was rehybridized with a 5S rRNA probe (5S rRNA). (C) A DNA blot hybridization pattern with the CEN probe after HpaII digestion demonstrates that centromeric repeat arrays hypomethylated in Bor-4 were fully remethylated in F1 hybrids resulting from reciprocal crosses between strains Bor-4 and Ler. The lane labeled Ler + Bor-4 contains a 1:1 mixture of Ler and Bor-4 HpaII-digested genomic DNA and shows the hybridization pattern expected if no remethylation occurred in the F1 hybrids.