DNA with base pair mismatches was prepared by annealing mixtures of genetically marked DNA from bacteriophage lambda. This heteroduplex DNA was used to transfect bacteria under conditions minimizing recombination. Genetic analysis of the progeny phages indicates that: (i) Mismatch repair occurs, usually giving rise to a DNA molecule with one chain with the genotype arising from repair and one p...

Seventeen different species of Legionella, 12 serogroups of Legionella pneumophila, and 2 Legionella-like amoebal pathogens (LLAP1 and Sarcobium lyticum) were examined by heteroduplex analysis of PCR products of the 5S rRNA gene. Eight different banding patterns were identified, indicating that heteroduplex analysis of this gene can be used to classify these bacteria according to base substitut...

Heteroduplexes formed between genes on homologous chromosomes are intermediates in meiotic recombination. In the HIS4 gene of Saccharomyces cerevisiae, most mutant alleles at the 5' end of the gene have a higher rate of meiotic recombination (gene conversion) than mutant alleles at the 3' end of the gene. Such gradients are usually interpreted as indicating a higher frequency of heteroduplex fo...

Endonuclease VII is a Holliday-structure resolving enzyme of phage T4 which cleaves at junctions of branched DNAs and at mispairings. In extension of these findings we report the following: i) Endonuclease VII can discriminate between a large heteroduplex loop and a TT mismatch arranged in tandem, 6 nt distant from each other, in the same heteroduplex molecule. The enzyme cleaves two nucleotide...

ATP hydrolysis by MutS homologues is required for the function of these proteins in mismatch repair. However, the function of ATP hydrolysis in the repair reaction is not very clear. We have examined the role of ATP hydrolysis in oligomerization of Thermus aquaticus (Taq) MutS protein in solution. Analytical gel filtration and cross-linking of MutS protein with disuccinimidyl suburate suggest t...

Brome mosaic virus (BMV) is a tripartite genome, positive-sense RNA virus of plants. Previously it was demonstrated that local hybridization between BMV RNAs (RNA-RNA heteroduplex formation) efficiently promotes non-homologous RNA recombination. In addition, studies on the role of the BMV polymerase in RNA recombination suggested that the location of non-homologous crossovers depends mostly on ...

We describe a simple method for creating libraries of chimeric DNA sequences derived from homologous parental sequences. A heteroduplex formed in vitro is used to transform bacterial cells where repair of regions of non-identity in the heteroduplex creates a library of new, recombined sequences composed of elements from each parent. Heteroduplex recombination provides a convenient addition to e...

A fluorescent heteroduplex method was developed to assess the presence of 16S rRNA gene (rDNA) sequences from Bacillus anthracis and close relatives in PCR-amplified 16S rDNA sequence mixtures from environmental samples. The method uses a single-stranded, fluorescent DNA probe, 464 nucleotides in length, derived from a B. anthracis 16S rRNA gene. The probe contains a unique, engineered deletion...

Heteroduplex molecules of pneumococcal DNA, prepared by cross-annealing resolved complementary strands, have been used as donors in transformation. A number of pairs of genetic markers are situated exclusively in the trans configuration in these heteroduplexes. Insertion of two markers from trans configuration into opposite DNA strands of a recipient genome should result in their segregation af...

Spontaneous recombination between direct repeats at the adenine phosphoribosyltransferase (APRT) locus in ERCC1-deficient cells generates a high frequency of rearrangements that are dependent on the process of homologous recombination, suggesting that rearrangements are formed by misprocessing of recombination intermediates. Given the specificity of the structure-specific Ercc1/Xpf endonuclease...