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. 2021 Aug 2;10:e66234. doi: 10.7554/eLife.66234

Figure 2. Fluorescence microscopy reveals uniparental nuclear inheritance in the wild-type crosses.

(A) Crosses of GFP-H4 tagged H99α and mCherry-H4 tagged KN99a revealed the presence of both fluorescent markers in most spore chains along with uniparental nuclear inheritance in rare cases (~1%). In these few sporulating basidia, only one of the fluorescent signals was observed in the spore chains, reflecting the presence of only one parental nucleus in these basidia. (B) Crosses involving GFP-H4 tagged VYD135α and mCherry-H4 tagged KN99a revealed the presence of spore chains with only one fluorescent color. In the majority of basidia that have both parental nuclei, marked by both GFP and mCherry signals, spore chains are not produced, consistent with a failure of meiosis in these basidia. Scale bar, 10 µm.

Figure 2.

Figure 2—figure supplement 1. Dynamics of sexual reproduction and sporulation analyzed with C. neoformans strains expressing nuclear-localized fluorescent reporter proteins.

Figure 2—figure supplement 1.

(A) A cartoon depicting various stages of sexual reproduction in C. neoformans, from the formation of conjugation tube to sporulation, and possible dynamics of the nuclei at these different stages. After the cell-cell fusion, tagged proteins assort into both nuclei and yield a yellow/orange fluorescence color as a result of the mixing of the green and red signals. Cartoons in the box show hypothetical scenarios where uniparental nuclear inheritance occurs after the loss of one parental nucleus. (B) Direct fluorescence microscopy images showing the status of GFP-H4 tagged and mCherry-H4 tagged nuclei in post-mating hyphae as well as in spores. Both GFP and mCherry fluorescent colors were observed in hyphae and spores as hypothesized in (A). Scale bar, 10 µm.
Figure 2—figure supplement 2. Nuclear dynamics during sporulation in the wild-type and VYD135α crosses.

Figure 2—figure supplement 2.

GFP-H4 and mCherry-H4 tagging revealed different localization patterns in the (A) wild-type H99α×KN99a and (B) VYD135α×KN99a crosses. Wild-type spore chains mostly harbored both the nuclear stains as a result of bisexual meiosis. On the other hand, basidia with only one of the parental nuclei produced spores in VYD135α×KN99a crosses; basidia with both nuclei failed to produce spore chains and, as a result, remained as bald basidia. Scale bar, 10 µm.