Unique C-terminal region of Hap3 is required for methanol-regulated gene expression in the methylotrophic yeast Candida boidinii

Abstract

The Hap complex of the methylotrophic yeast Candida boidinii was found to be required for methanol-regulated gene expression. In this study, we performed functional characterization of CbHap3p, one of the Hap complex components in C. boidinii. Sequence alignment of Hap3 proteins revealed the presence of a unique extended C-terminal region, which is not present in Hap3p from Saccharomyces cerevisiae (ScHap3p), but is found in Hap3p proteins of methylotrophic yeasts. Deletion of the C-terminal region of CbHap3p (D256-292 or D107-237) diminished activation of methanol-regulated genes and abolished the ability to grow on methanol, but did not affect nuclear localization or DNA-binding ability. However, deletion of the N-terminal region of CbHap3p (D1-20) led to not only a growth defect on methanol and a decreased level of methanol-regulated gene expression, but also impaired nuclear localization and binding to methanol-regulated gene promoters. We also revealed that CbHap3p could complement the growth defect of the Schap3D strain on glycerol, although ScHap3p could not complement the growth defect of a Cbhap3D strain on methanol. We conclude that the unique C-terminal region of CbHap3p contributes to maximum activation of methanol-regulated genes, whilst the N-terminal region is required for nuclear localization and binding to DNA.

Phosphoregulation of the transcription factor Mxr1 plays a crucial role in the concentration‐regulated methanol induction in Komagataella phaffii

“…Some of these transcription factors, such as the homologs of Saccharomyces cerevisiae Adr1, KpMxr1 and CbTrm2, are involved in derepression (Lin-Cereghino et al, 2006;Sasano et al, 2010). Three kinds of transcription factors are involved in methanol induction; (i) Mpp1 (HpMpp1 and KpMit1) (Leão-Helder et al, 2003;Wang et al, 2016), (ii) Trm1 (CbTrm1 and KpTrm1) (Sahu et al, 2014;Sasano et al, 2008), and (iii) the CbHap complex (Oda et al, 2015(Oda et al, , 2016 (Figure S1b).…”