Size-dependent palindrome-induced intrachromosomal recombination in yeast.
Palindromic and quasi-palindromic sequences are important DNA motifs found in various cis-acting genetic elements, but are also known to provoke different types of genetic alterations. The instability of such motifs is clearly size-related and depends on their potential to adopt secondary structures known as hairpins and cruciforms. Here we studied the influence of palindrome size on recombination between two directly repeated copies of the yeast CYC1 gene leading to the loss of the intervening sequence ("pop-out" recombination). We show that palindromes inserted either within one copy or between the two copies of the CYC1 gene become recombinogenic only when they attain a certain critical size and we estimate this critical size to be about 70 bp. With the longest palindrome used in this study (150 bp) we observed a more than 20-fold increase in the pop-out recombination. In the sae2/com1 mutant the palindrome-stimulated recombination was completely abolished. Suppression of palindrome recombinogenicity may be crucial for the maintenance of genetic stability in organisms containing a significant number of large palindromes in their genomes, like humans.
Lisnić
Berislav
B
Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, Laboratory of Biology and Microbial Genetics, Pierottijeva 6, Zagreb, Croatia.
Svetec
Ivan-Kresimir
IK
Stafa
Anamarija
A
Zgaga
Zoran
Z
D001483:Base Sequence; D015825:Chromosomes, Fungal; D045566:DNA, Cruciform / Q000235:genetics / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004720:Endonucleases; D042822:Genomic Instability / Q000235:genetics; D055029:Inverted Repeat Sequences / Q000502:physiology*; D008969:Molecular Sequence Data; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D017384:Sequence Deletion
D045566:DNA, Cruciform; D004271:DNA, Fungal; C107849:SAE2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D004720:Endonucleases