Ssn6 has dual roles in Candida albicans filament development through the interaction with Rpd31

Ssn6 is a crucial regulator of morphological transition and virulence in the fungal pathogen Candida albicans. Ssn6 has previously been reported to act in complex with the transcriptional repressor Tup1. Here, we report that Ssn6 also interacts with the histone deacetylase Rpd31, independently of Tup1. The ssn6/rpd31 double mutant strain formed elongated filaments, but failed to form filament extension, and this coincided with the down-regulation of the filament extension gene UME6. Occupancy patterns of Ssn6 and Rpd31 differed at the promoters of UME6 and the metabolic gene INO1. These findings indicate that, in C. albicans, Ssn6 has dual roles in filament development, depending on the interaction with Rpd31.