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

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 (Δ256–292 or Δ107–237) 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 (Δ1–20) 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 Schap3Δ strain on glycerol, although ScHap3p could not complement the growth defect of a Cbhap3Δ 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

Molecular Characterization of Hap Complex Components Responsible for Methanol-Inducible Gene Expression in the Methylotrophic Yeast Candida boidinii.

We identified genes encoding components of the Hap complex, CbHAP2, CbHAP3, and CbHAP5, as transcription factors regulating methanol-inducible gene expression in the methylotrophic yeast Candida boidinii. We found that the Cbhap2Δ, Cbhap3Δ, and Cbhap5Δ gene-disrupted strains showed severe growth defects on methanol but not on glucose and nonfermentable carbon sources such as ethanol and glycerol. In these disruptants, the transcriptional activities of methanol-inducible promoters were significantly decreased compared to those of the wild-type strain, indicating that CbHap2p, CbHap3p, and CbHap5p play indispensable roles in methanol-inducible gene expression. Further molecular and biochemical analyses demonstrated that CbHap2p, CbHap3p, and CbHap5p localized to the nucleus and bound to the promoter regions of methanol-inducible genes regardless of the carbon source, and heterotrimer formation was suggested to be necessary for binding to DNA. Unexpectedly, distinct from Saccharomyces cerevisiae, the Hap complex functioned in methanol-specific induction rather than glucose derepression in C. boidinii. Our results shed light on a novel function of the Hap complex in methanol-inducible gene expression in methylotrophic yeasts

Pantoea ananatis を宿主としたテルペノイド発酵生産基盤技術の開発

2021【要旨

Impact of the serum bone-specific alkaline phosphatase level at the initiation of hemodialysis therapy for end-stage renal disease on cardiovascular events

Background: Patients with end-stage renal disease (ESRD) have high rates of hospitalization for cardiovascular (CV) events and short-term mortality after the initiation of hemodialysis (HD) therapy. To improve outcomes, it is important to identify predictive laboratory markers. We investigated whether the serum bone-specific alkaline phosphatase (BAP) level at the initiation of HD therapy for ESRD was associated with adverse events. Methods: This was a retrospective cohort study of 47 ESRD outpatients who were referred to our clinic for HD. The serum BAP level was measured within 1 month after the initiation of HD. Patients were divided into high-BAP and low-BAP groups according to the median serum BAP level (24.6 U/L). The impact of the serum BAP level on CV events (coronary artery disease, peripheral arterial disease, cerebrovascular disease, other CV events including aortic dissection, and mortality) was investigated. Results: During a median follow-up period of 72 months, CV events occurred in 14 patients (29.8%). Kaplan–Meier analysis showed that the disease-free and overall survival rates were lower in the high-BAP group than in the low-BAP group (p = 0.003 and p = 0.037, respectively, log-rank test). After adjustment for age, sex, and other confounding factors, Cox proportional hazards analysis found that the high-BAP group had a 5.9-fold higher rate of CV events than the low-BAP group (hazard ratio: 5.89; 95% confidence interval: 1.184–29.309; p = 0.030). Conclusions: The serum BAP level at the initiation of HD therapy for ESRD is a useful non-invasive biomarker for predicting CV events