Involvement of the Noncanonical Polyadenylation Polymerase Cid14 in Fungal Azole Resistance in the Pathogen Cryptococcus neoformans

The yeast noncanonical polyadenylation polymerase Cid14 was originally identified from fission yeast and plays a critical role in the TRAMP complex. This protein is a cytoplasmic cofactor and regulator of RNA-degrading exosomes. Cid14 is highly conserved from yeast to animals and has been demonstrated to play key roles in the regulation of RNA surveillance, nutrition metabolism, and growth in model organisms, but not yet in Cryptococcus neoformans (C. neoformans). Here, we report the identification of a gene encoding an equivalent Cid14 protein, named CID14, in the fungal pathogen C. neoformans. To obtain insights into the function of Cid14, we created a mutant strain, cid14 Delta , with the CRISPR-Cas9 editing tool. Disruption of CID14 impaired cell membrane stability. Further investigations revealed the defects of the cid14 Delta mutant in resistance to low carbohydrate levels. Meanwhile, significantly, the ability to grow under flucytosine stress was decreased in the cid14 Delta, mutant. More importantly, our results showed that the cid14 Delta mutant does not affect yeast virulence but exhibits multidrug resistance to azole. Our work is the first to suggest that Cid14 plays critical roles in azole resistance by affecting Afr1, which is chiefly responsible for azole excretion in the ABC (ATP-binding cassette) transporter.