Deletion of the sex-determining gene SXI1 alpha enhances the spread of mitochondrial introns in Cryptococcus neoformans

作者：Yan, Zhun; Li, Zhimin; Yan, Li; Yu, Yongting; Cheng, Yi; Chen, Jia; Liu, Yunyun; Gao, Chunsheng; Zeng, Liangbin; Sun, Xiangping; Guo, Litao; Xu, Jianping^*

来源：Mobile DNA, 2018, 9(1): 24.

DOI：10.1186/s13100-018-0129-0

• HEG
• Intron
• Mating type
• mtDNA inheritance

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) alpha-specific homeodomain gene SXI1 alpha. C. neoformans has two mating types, MATa and MAT alpha. In typical crosses between strains of the two mating types, only a small portion (< 7%) of diploid fusants inherited the HEGs from the MAT alpha parent. However, disruption of the SXI1 alpha gene resulted in the majority (> 95%) of the diploid fusants inheriting the HEG-containing introns from the MAT alpha parent, a frequency significantly higher than those of intronless mitochondrial genes.
Conclusions: Our results suggest that SXI1 alpha not only determines uniparental mitochondrial inheritance but also inhibits the spread of HEG-containing introns in the mitochondrial genome in C. neoformans.

• 出版日期2018-7-17
• 单位中国农业科学院