The Pichia pastoris transmembrane protein GT1 is a glycerol transporter and relieves the repression of glycerol on AOX1 expression

Promoter of alcohol oxidase I (PAOX1) is the most efficient promoter involved in the regulation of recombinant protein expression in Pichia pastoris (P. pastoris). PAOX1 is tightly repressed by the presence of glycerol in the culture medium; thus, glycerol must be exhausted before methanol can be taken up by P. pastoris and the expression of the heterologous protein can be induced. In this study, a candidate glycerol transporter (GT1, GeneID: 8197545) was identified, and its role was confirmed by further studies (e.g. bioinformatics analysis, heterologous complementation in Schizosaccharomyces pombe (S. pombe)). When GT1 is co-expressed with enhanced green fluorescent protein (EGFP), it localizes to the membrane and S. pombe carrying gt1 but not the wild-type strain can grow on medium containing glycerol as the sole carbon source. The present study is the first to report that AOX1 in the X-33gt1 mutant can achieve constitutive expression in medium containing glycerol; thus, knocking down gt1 can eliminate the glycerol repression of PAOX1 in P. pastoris. These results suggest that the glycerol transporter may participate in the process of PAOX1 inhibition in glycerol medium

Kaplan-Meier plots of breast cancer patient survival based on WDR5 expression.

<p>Plots represent DFS from the main analysis of A) GSE24450, B) GSE1456, and C) GSE4922 data sets, and subgroup analysis of D) anthracycline treated and E) untreated tumours from GSE24450 data. The p value and hazard ratio (HR) are shown in each subplot. The number of patients is shown in the brackets in the legends. Data on the breast cancer specific death over 10 years using GSE24450 are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124964#pone.0124964.s001" target="_blank">S1 Fig</a>.</p

Summarized statistics of the association between <i>WDR5</i> gene expression and breast cancer patient survival.

<p>The p value and hazard ratio (HR) of tumours over-expressing <i>WDR5</i> are depicted below. In the ‘Subgroup’ column, ‘Anthr+’ and ‘Anthr-’ labels represent the anthracycline treated and untreated group respectively, and ‘main’ means all samples are used in the analysis. The number of patients is shown in the ‘Sample’ column, with the number of events listed in the brackets.</p><p>Summarized statistics of the association between <i>WDR5</i> gene expression and breast cancer patient survival.</p

Boxplots showing the effect of <i>WDR5</i> knockdown on cell viability in the MCF7 breast cancer cell line.

<p>Boxplots showing the effect of <i>WDR5</i> knockdown on cell viability in the MCF7 breast cancer cell line.</p

Description of the data sets used for gene expression survival analysis.

<p>Description of the data sets used for gene expression survival analysis.</p