Structures of naturally evolved CUP1 tandem arrays in yeast indicate that these arrays are generated by unequal nonhomologous recombination.
Bottom Line: In the yeast Saccharomyces cerevisiae, most strains contain tandemly duplicated copies of CUP1, a gene that encodes a copper-binding metallothionein.By screening 101 natural isolates of S. cerevisiae, we identified five different types of CUP1-containing repeats, as well as strains that only had one copy of CUP1.A comparison of the DNA sequences of these strains indicates that the CUP1 tandem arrays were generated by unequal nonhomologous recombination events from strains that had one CUP1 gene.
Affiliation: Department of Molecular Genetics and Microbiology and University Program in Genetics and Genomics, Duke University Medical Center, Durham, North Carolina 27710.Show MeSH
Related in: MedlinePlus
Mentions: Variation in the number of CUP1 repeats in tandem arrays of different yeast strains has been observed previously by Southern analysis (Welch et al. 1983). In addition, in the analysis of the 100-genome strains, estimates of the numbers of repeats per strain were made based on the number of times CUP1 sequences were present relative to single-copy sequences (P. K. Strope, D. A. Skelly, S. G. Kozmin, G. Mahadevan, E. A. Stone, P. M. Magwene, F. S. Dietrich, and J. H. McCusker, personal communication). We used Southern analysis to determine the number of repeats in 10 strains that were part of the 100-genome strain analysis, as well as three other yeast strains (S288c, W303-1A, and YJM789). For this analysis, genomic DNA was treated with EcoRI which does not have a recognition sequence within the repeats (Figure 2A). Southern analysis of the strains is depicted in Figure 5.
Affiliation: Department of Molecular Genetics and Microbiology and University Program in Genetics and Genomics, Duke University Medical Center, Durham, North Carolina 27710.