Nitrogen source and the retrograde signalling pathway affect detection, not generation, of the [URE3] prion.
[URE3] is an infectious (prion) inactive amyloid form of Ure2p, a regulator of nitrogen catabolism. [URE3] clones are selected on NH(4) (+), using their derepressed expression of DAL5 to allow uptake of ureidosuccinate (USA). We previously reported that mks1Delta prevents generation of [URE3] and others reported that glutamate in the medium or the elevated glutamate in mks1Delta strains blocks [URE3] generation. We show here that elevated glutamate does not block [URE3] generation, but that neither does mks1Delta. Rather, a post-transcriptional effect on DAL5 of mks1Delta through the retrograde regulation pathway prevents detection of [URE3] prion-containing colonies. Moreover, the presence of both ammonia and glutamate blocks USA uptake in a known [URE3] strain, so that detection of the prion is prevented, rather than its generation.
Edskes
Herman K
HK
Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA.
Naglieri
Benedetta M
BM
Wickner
Reed B
RB
D018698:Glutamic Acid / Q000378:metabolism; D005979:Glutathione Peroxidase; D007656:Ketoglutaric Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D011328:Prions / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014498:Uracil / Q000378:metabolism
C503299:DAL5 protein, S cerevisiae; D007656:Ketoglutaric Acids; C080921:MKS1 protein, S cerevisiae; D026901:Membrane Transport Proteins; D011328:Prions; D000644:Quaternary Ammonium Compounds; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D018698:Glutamic Acid; D014498:Uracil; D005979:Glutathione Peroxidase; C067020:URE2 protein, S cerevisiae; D009584:Nitrogen