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. 2020 Oct 16;9:e62337. doi: 10.7554/eLife.62337

Figure 5. A single SNP in Y9 MMS21 contributes to the plasmid instability phenotype.

(A) Introduction of the Y9 MMS21 allele into BY4742 haploid cells is not sufficient to significantly lower plasmid instability. (B) However, removal of the Y9 MMS21 allele but not the BY4742 MMS21 allele increases plasmid stability in BY4742/Y9 heterozygous diploids, showing that the Y9 allele of MMS21 plays an important role in the Y9 plasmid instability phenotype. **p<0.001, Kruskal-Wallis test, n.s. = not significant. (C) Plasmid prevalence (by plasmid class) for each MMS21 Thr9Ile genotype within 1011 sequenced S. cerevisiae strains. Plasmid data and genotypes from Peter et al., 2018. Strains with the Y9 MMS21 allele (I69) have a lower frequency of harboring 2μ plasmids in general, and A-type 2μ plasmids, in particular. However, this effect can be confounded by the phylogenetic relatedness of these strains.

Figure 5.

Figure 5—figure supplement 1. Comparative analysis of MMS21 and flanking regions.

Figure 5—figure supplement 1.

We show all differences between Y9 and BY4742 in the MMS21 ORF and flanking intergenic regions (chrV:120199–121571, − strand). We also show genotypes for Y12 (closely-related non-permissive strain) and UC5 (closely-related permissive strain), and show SNPs where genotype is congruent (in black) or incongruent (in gray) with plasmid status. ‘syn’=synonymous, ‘mis’=missense.
Figure 5—figure supplement 2. Sequence of MMS21 codon 69 across the Saccharomyces sensu stricto clade, as well as selected S. cerevisiae strains and two outgroup Naumovozyma species.

Figure 5—figure supplement 2.

Species cladogram was adapted from previous studies (Naseeb, 2018; Borneman and Pretorius, 2014). This analysis shows that the Thr69 allele of MMS21 is ancestral in S. cerevisiae but is not universally conserved in closely-related species.
Figure 5—figure supplement 3. The Thr69Ile polymorphism is located at the Mms21-Smc5 binding interface.

Figure 5—figure supplement 3.

(A) The Thr69Ile polymorphism occurs in the third alpha-helix in the Mms21 N-terminal domain. The C-terminal domain of MMS21 encodes the SUMO E3-ligase associated RING domain. (B) Schematic of co-crystal structure of Mms21 with the coiled coil domain of Smc5 (PDB: 3HTK, adapted from Figure 1, Duan et al., 2009) shows that the Thr69 residue (*) in the N-terminal domain is at the direct binding interface between the two proteins. (C) Cartoon of Smc5/6 complex in S. cerevisiae showing the Mms21-Smc5 interaction, reproduced from Figure 1 (right panel), Stephan et al., 2011.
© 2015, Stephan et al.
https://creativecommons.org/licenses/by-nc-nd/3.0/ Reproduced from Figure 1 (right panel), Stephan et al., 2011, under the terms of a CC-BY-NC-ND 3.0 license. This panel is not available under the terms of the CC-BY 4.0 license and any further reproduction must adhere to the terms of the original license.