FIG 1 .

Bisexual mating of Cryptococcus neoformans. Under mating-inducing conditions, a and α cells undergo cell fusion. The early events during mating are controlled by the pheromone sensing and response pathway. Following cell fusion, the original zygote sends out the dikaryotic hypha, which grows filamentously as heterokaryotic dikaryons. Nuclear fusion and meiosis occur in the basidium formed at the tip of the aerial hypha. Four chains of spores are then generated from the basidium. Transcription factor Mat2 is essential for cell fusion (26), the mating-type-specific homeodomain complex Sxi1α/Sxi2a is specifically required for dikaryotic hypha formation and the completion of sexual development (15, 16), and the transcription factor Znf2 is essential for hyphal formation under all conditions (26, 27).