Author:
Barsoum Emad,Martinez Paula,Åström Stefan U.
Abstract
Theoretical models predict that selfish DNA elements require host sex to persist in a population. Therefore, a transposon that induces sex would strongly favor its own spread. We demonstrate that a protein homologous to transposases, called α3, was essential for mating type switch in Kluyveromyces lactis. Mutational analysis showed that amino acids conserved among transposases were essential for its function. During switching, sequences in the 5′ and 3′ flanking regions of the α3 gene were joined, forming a DNA circle, showing that α3 mobilized from the genome. The sequences encompassing the α3 gene circle junctions in the mating type α (MATα) locus were essential for switching from MATα to MATa, suggesting that α3 mobilization was a coupled event. Switching also required a DNA-binding protein, Mating type switch 1 (Mts1), whose binding sites in MATα were important. Expression of Mts1 was repressed in MATa/MATα diploids and by nutrients, limiting switching to haploids in low-nutrient conditions. A hairpin-capped DNA double-strand break (DSB) was observed in the MATa locus in mre11 mutant strains, indicating that mating type switch was induced by MAT-specific DSBs. This study provides empirical evidence for selfish DNA promoting host sexual reproduction by mediating mating type switch.
Publisher
Cold Spring Harbor Laboratory
Subject
Developmental Biology,Genetics
Cited by
75 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献