High impact information on JEN1

• The disruption of JEN1 from Candida albicans impairs the transport of lactate [1].
• The chimaeric protein Jen1p-GFP is targeted to the plasma membrane via a Sec6-dependent process; upon treatment with glucose, it is endocytosed via END3 and targeted for degradation in the vacuole [2].
• For example, a strain expressing FLO1 under control of the JEN1 promoter flocculates at a low glucose concentration [3].
• Activation of the JEN1 promoter requires the Snf1 protein kinase, but multiple regulatory elements most likely combine to provide the linear relationship between JEN1 promoter activity and sugar concentration [3].
• JEN1 promoter repression is specific to carbon source; heat or cold shock, osmotic stress, DNA damage, and nitrogen starvation do not significantly affect promoter activity [3].

Biological context of JEN1

• Transformation of the mutant with a yeast genomic library allowed the isolation of the gene JEN1 that restored lactate transport [4].
• The lactate-proton symport of Saccharomyces cerevisiae is encoded by JEN1 [4].
• A value of 15.1 min was found for the half-life of JEN1 mRNA, showing the involvement of a glucose-induced mechanism of mRNA degradation [5].
• Mapping of the 5'UTRs and 3'UTRs of JEN1 transcripts revealed multiple transcription start-sites located at position -51, +391 or +972, depending on the cell culture conditions [6].
• Pichia pastoris was transformed with an integrative plasmid containing the JEN1 gene [7].

Anatomical context of JEN1

• In the yeast Saccharomyces cerevisiae, the first step in lactate metabolism is its transport across the plasma membrane, a proton symport process mediated by the product of the gene JEN1 [8].

Associations of JEN1 with chemical compounds

• JEN1 promoter activity is a linear function of glucose concentration when organisms are grown at a steady-state glucose concentration below 1 g/liter [3].
• Certain sugars, including glucose, fructose, and mannose, repress the promoter of JEN1, which encodes a lactate-pyruvate transporter, in a dose-dependent manner [3].
• Cat8p, the activator of gluconeogenic genes in Saccharomyces cerevisiae, regulates carbon source-dependent expression of NADP-dependent cytosolic isocitrate dehydrogenase (Idp2p) and lactate permease (Jen1p) [9].
• Additional deletion of the JEN1 lactate transporter gene completely blocked uptake of lactate and pyruvate [10].
• Isogenic strains, deleted in genes encoding enzymes involved in lactic acid metabolism, did not express JEN1, indicating an association of the intracellular metabolism of the acid to the transcription of the permease gene [5].
• Ubiquitylation and endocytosis of Jen1 are induced within minutes in response to glucose addition [11].

Physical interactions of JEN1

• In this report we demonstrate that, in addition to these regulators, the Hap2/3/4/5 complex interacts specifically with a CAAT-box element in the JEN1 promoter, and acts to derepress JEN1 expression [8].

Regulatory relationships of JEN1

• Expression studies revealed that JEN1 is regulated negatively by the repressors Mig1p and Mig2p, and that Cat8p is needed for full derepression of the gene under non-fermentative growth conditions [9].

Other interactions of JEN1

• The system is based on a Saccharomyces cerevisiae pyk1 mae1 jen1 triple-deletion strain that is auxotrophic for pyruvate and deficient in monocarboxylate uptake [12].

Analytical, diagnostic and therapeutic context of JEN1

• Thus, a JEN1 promoter-reporter system appears to provide a good living cell biosensor for the concentration of certain sugars [3].
• After 24 h of methanol induction, Northern and Western blotting analyses indicated the expression of JEN1 in the transformants [7].
• In a DNA microarray analysis, GDR19 highly expressed many more genes, including JEN1, in the presence of glucose compared with the parental strain B29 [13].

References