Deletion of the sex-determining gene SXI1α enhances the spread of mitochondrial introns in Cryptococcus neoformans Academic Article uri icon

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  • Background: Homing endonuclease genes (HEGs) are widely distributed genetic elements in the mitochondrial genomes of a diversity of eukaryotes. Due to their ability to self-propagate within and between genomes, these elements can spread rapidly in populations. Whether and how such elements are controlled in genomes remains largely unknown. Results: Here we report that the HEG-containing introns in the mitochondrial COX1 gene in Cryptococcus neoformans are mobile and that their spread in sexual crosses is influenced by mating type (MAT) α-specific homeodomain gene SXI1α. C. neoformans has two mating types, MATa and MATα . In typical crosses between strains of the two mating types, only a small portion (< 7%) of diploid fusants inherited the HEGs from the MATα parent. However, disruption of the SXI1α gene resulted in the majority (> 95%) of the diploid fusants inheriting the HEG-containing introns from the MATα parent, a frequency significantly higher than those of intronless mitochondrial genes. Conclusions: Our results suggest that SXI1α not only determines uniparental mitochondrial inheritance but also inhibits the spread of HEG-containing introns in the mitochondrial genome in C. neoformans.


  • Yan, Zhun
  • Li, Zhimin
  • Yan, Li
  • Yu, Yongting
  • Cheng, Yi
  • Chen, Jia
  • Liu, Yunyun
  • Gao, Chunsheng
  • Zeng, Liangbin
  • Sun, Xiangping
  • Guo, Litao
  • Xu, Jianping

publication date

  • December 2018