Identification of the Transcription Factor Znc1p, which Regulates the Yeast-to-Hypha Transition in the Dimorphic Yeast Yarrowia lipolytica

Abstract

The dimorphic yeast Yarrowia lipolytica is used as a model to study fungal differentiation because it grows as yeast-like cells or forms hyphal cells in response to changes in environmental conditions. Here, we report the isolation and characterization of a gene, ZNC1, involved in the dimorphic transition in Y. lipolytica. The ZNC1 gene encodes a 782 amino acid protein that contains a Zn(II)2C6 fungal-type zinc finger DNA-binding domain and a leucine zipper domain. ZNC1 transcription is elevated during yeast growth and decreases during the formation of mycelium. Cells in which ZNC1 has been deleted show increased hyphal cell formation. Znc1p-GFP localizes to the nucleus, but mutations within the leucine zipper domain of Znc1p, and to a lesser extent within the Zn(II)2C6 domain, result in a mislocalization of Znc1p to the cytoplasm. Microarrays comparing gene expression between znc1::URA3 and wild-type cells during both exponential growth and the induction of the yeast-to-hypha transition revealed 1,214 genes whose expression was changed by 2-fold or more under at least one of the conditions analyzed. Our results suggest that Znc1p acts as a transcription factor repressing hyphal cell formation and functions as part of a complex network regulating mycelial growth in Y. lipolytica.

Latent homology and convergent regulatory evolution underlies the repeated emergence of yeasts

“…Crucially, Ace2, the principal regulator of cell separation genes Eng1 and Agn1 (ref. 20) as well as Mhy1 and Znc1, which were previously implicated in filamentous/yeast transitions in dimorphic fungi 21,22 , also belong to this TF family. Therefore, it is likely that the parallel diversification of this TF family corresponds to the elaboration of the regulatory repertoire governing the maintenance of the unicellular life stage and switches between filamentous and yeast forms.…”

Spermine modulates fungal morphogenesis and activates plasma membrane H+-ATPase during yeast to hyphae transition

“…Microarray and proteomic analysis of Y. lipolytica during the yeast-to-hypha transition revealed several genes and proteins involved in morphogenetic transition ( Morín et al, 2007 ; Morales-Vargas et al, 2012 ). The complete genome sequence and efficient genetic tools have also provided important insights on signaling pathways and transcriptional factors required for morphogenesis in Y. lipolytica ( Cervantes-Chávez et al, 2009 ; Martinez-Vazquez et al, 2013 ). In addition, this non-pathogenic fungus has interesting similarities to the highly virulent pathogen Candida albicans ( Herrero et al, 1999 ).…”

A molecular genetic toolbox for Yarrowia lipolytica

“…Fluorescent protein studies in Y. lipolytica have encompassed tagging for localization of Fat1p, Fat4p, and Faa1p using plasmids [33, 34]. Similarly, hybrid promoter studies have utilized fluorescent proteins [35], and transcription factors have been localized using a GFP-fusion expressed from a plasmid [36]. However, sets of Y. lipolytica strains with GFP tagged organelles are not available.…”