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1.
PLoS One ; 19(2): e0299200, 2024.
Article in English | MEDLINE | ID: mdl-38359013

ABSTRACT

[This corrects the article DOI: 10.1371/journal.pone.0137820.].

2.
FEMS Yeast Res ; 18(6)2018 09 01.
Article in English | MEDLINE | ID: mdl-29931271

ABSTRACT

Fission yeast 'cut' mutants show defects in temporal coordination of nuclear division with cytokinesis, resulting in aberrant mitosis and lethality. Among other causes, the 'cut' phenotype can be triggered by genetic or chemical perturbation of lipid metabolism, supposedly resulting in shortage of membrane phospholipids and insufficient nuclear envelope expansion during anaphase. Interestingly, penetrance of the 'cut' phenotype in mutants of the transcription factor cbf11 and acetyl-coenzyme A carboxylase cut6, both related to lipid metabolism, is highly dependent on growth media, although the specific nutrient(s) affecting 'cut' occurrence is not known. In this study, we set out to identify the growth media component(s) responsible for 'cut' phenotype suppression in Δcbf11 and cut6-621 cells. We show that mitotic defects occur rapidly in Δcbf11 cells upon shift from the minimal EMM medium ('cut' suppressing) to the complex YES medium ('cut' promoting). By growing cells in YES medium supplemented with individual EMM components, we identified ammonium chloride, an efficiently utilized nitrogen source, as a specific and potent suppressor of the 'cut' phenotype in both Δcbf11 and cut6-621. Furthermore, we found that ammonium chloride boosts lipid droplet formation in wild-type cells. Our findings suggest a possible involvement of nutrient-responsive signaling in 'cut' suppression.


Subject(s)
Ammonium Chloride/pharmacology , Lipid Metabolism/drug effects , Mitosis/drug effects , Schizosaccharomyces/drug effects , Schizosaccharomyces/genetics , Acetyl-CoA Carboxylase/genetics , Ammonium Chloride/chemistry , Ammonium Chloride/metabolism , Culture Media/chemistry , Lipid Droplets/drug effects , Lipid Droplets/metabolism , Lipid Metabolism/genetics , Mitosis/genetics , Mutation , Penetrance , Phenotype , Schizosaccharomyces/growth & development , Schizosaccharomyces/metabolism , Schizosaccharomyces pombe Proteins/genetics , Transcription Factors/genetics
3.
PLoS One ; 10(9): e0137820, 2015.
Article in English | MEDLINE | ID: mdl-26366556

ABSTRACT

BACKGROUND: Cbf11 and Cbf12, the fission yeast CSL transcription factors, have been implicated in the regulation of cell-cycle progression, but no specific roles have been described and their target genes have been only partially mapped. METHODOLOGY/PRINCIPAL FINDINGS: Using a combination of transcriptome profiling under various conditions and genome-wide analysis of CSL-DNA interactions, we identify genes regulated directly and indirectly by CSL proteins in fission yeast. We show that the expression of stress-response genes and genes that are expressed periodically during the cell cycle is deregulated upon genetic manipulation of cbf11 and/or cbf12. Accordingly, the coordination of mitosis and cytokinesis is perturbed in cells with genetically manipulated CSL protein levels, together with other specific defects in cell-cycle progression. Cbf11 activity is nutrient-dependent and Δcbf11-associated defects are mitigated by inactivation of the protein kinase A (Pka1) and stress-activated MAP kinase (Sty1p38) pathways. Furthermore, Cbf11 directly regulates a set of lipid metabolism genes and Δcbf11 cells feature a stark decrease in the number of storage lipid droplets. CONCLUSIONS/SIGNIFICANCE: Our results provide a framework for a more detailed understanding of the role of CSL proteins in the regulation of cell-cycle progression in fission yeast.


Subject(s)
Schizosaccharomyces pombe Proteins/genetics , Schizosaccharomyces/genetics , Schizosaccharomyces/metabolism , Transcription Factors/metabolism , Cyclic AMP-Dependent Protein Kinases/genetics , Cytokinesis , Gene Expression Profiling/methods , Gene Expression Regulation, Fungal , Mitogen-Activated Protein Kinases/genetics , Mitosis , Schizosaccharomyces pombe Proteins/metabolism , Stress, Physiological , Transcription Factors/genetics
4.
BMC Biochem ; 12: 44, 2011 Aug 10.
Article in English | MEDLINE | ID: mdl-21831316

ABSTRACT

BACKGROUND: Acyl-acyl carrier protein thioesterases (acyl-ACP TEs) catalyze the hydrolysis of the thioester bond that links the acyl chain to the sulfhydryl group of the phosphopantetheine prosthetic group of ACP. This reaction terminates acyl chain elongation of fatty acid biosynthesis, and in plant seeds it is the biochemical determinant of the fatty acid compositions of storage lipids. RESULTS: To explore acyl-ACP TE diversity and to identify novel acyl ACP-TEs, 31 acyl-ACP TEs from wide-ranging phylogenetic sources were characterized to ascertain their in vivo activities and substrate specificities. These acyl-ACP TEs were chosen by two different approaches: 1) 24 TEs were selected from public databases on the basis of phylogenetic analysis and fatty acid profile knowledge of their source organisms; and 2) seven TEs were molecularly cloned from oil palm (Elaeis guineensis), coconut (Cocos nucifera) and Cuphea viscosissima, organisms that produce medium-chain and short-chain fatty acids in their seeds. The in vivo substrate specificities of the acyl-ACP TEs were determined in E. coli. Based on their specificities, these enzymes were clustered into three classes: 1) Class I acyl-ACP TEs act primarily on 14- and 16-carbon acyl-ACP substrates; 2) Class II acyl-ACP TEs have broad substrate specificities, with major activities toward 8- and 14-carbon acyl-ACP substrates; and 3) Class III acyl-ACP TEs act predominantly on 8-carbon acyl-ACPs. Several novel acyl-ACP TEs act on short-chain and unsaturated acyl-ACP or 3-ketoacyl-ACP substrates, indicating the diversity of enzymatic specificity in this enzyme family. CONCLUSION: These acyl-ACP TEs can potentially be used to diversify the fatty acid biosynthesis pathway to produce novel fatty acids.


Subject(s)
Phylogeny , Thiolester Hydrolases/classification , Thiolester Hydrolases/metabolism , Amino Acid Sequence , Biocatalysis , Cluster Analysis , Databases, Protein , Fatty Acids, Unsaturated/biosynthesis , Fatty Acids, Volatile/biosynthesis , Models, Molecular , Molecular Sequence Data , Plants/enzymology , Protein Conformation , Sequence Analysis, DNA , Substrate Specificity , Thiolester Hydrolases/chemistry
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