QRI1/YDL103C Summary Help

Standard Name QRI1 1
Systematic Name YDL103C
Alias UAP1
Feature Type ORF, Verified
Description UDP-N-acetylglucosamine pyrophosphorylase; catalyzes the formation of UDP-N-acetylglucosamine (UDP-GlcNAc), which is important in cell wall biosynthesis, protein N-glycosylation, and GPI anchor biosynthesis; protein abundance increases in response to DNA replication stress (2, 3 and see Summary Paragraph)
Chromosomal Location
ChrIV:276581 to 275148 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All QRI1 GO evidence and references
  View Computational GO annotations for QRI1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Regulators 1 genes
Large-scale survey
67 total interaction(s) for 63 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 8
  • Affinity Capture-RNA: 4
  • Biochemical Activity: 1
  • Reconstituted Complex: 8
  • Two-hybrid: 1

Genetic Interactions
  • Dosage Lethality: 2
  • Negative Genetic: 35
  • Positive Genetic: 8

Expression Summary
Length (a.a.) 477
Molecular Weight (Da) 53,476
Isoelectric Point (pI) 7.42
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrIV:276581 to 275148 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2004-02-11 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1434 276581..275148 2004-02-11 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000002261

UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) is the source of the first two GlcNAc moieties added during N-linked glycosylation of proteins and provides GlcNAc for synthesis of GPI anchors. In yeast, it is synthesized from fructose-6-phosphate (F6P) by the consecutive action of Gfa1p, Gna1p, Pcm1p, and Qri1p, although a different pathway (4, 5) is used in bacteria. UDP-GlcNAc is also the building block from which chitin, a linear polymer of beta-1,4-N-acetylglucosamine, is constructed. Chitin is a component of the cell wall deposited as a ring around the neck of the growing bud during cell division. Bud scars, the remnants of the chitinous primary septum seen on the surface of mother cells after division, are the primary repository of chitin (reviewed in 6).

QRI1, also known as UAP1, encodes UDP-N-acetylglucosamine pyrophosphorylase, which synthesizes UDP-GlcNAc from GlcNAc-1-P and UTP (2). GlcNAc-1-P is synthesized by Pcm1p. QRI1 is an essential gene; conditional depletion of Qri1p allows cells to continue to divide for four to five generations (1), but they have an abnormal, swollen appearance and are prone to bursting (2). Qri1p can also synthesize UDP-Glc from Glc-1-P, but not in sufficient amounts to replace Ugp1p, which provides most of the cellular UDP-Glc (2). Both human (OMIM) and Candida albicans UAP1 complement deletion of QRI1 (2).

Last updated: 2005-07-01 Contact SGD

References cited on this page View Complete Literature Guide for QRI1
1) Simon M, et al.  (1994) Sequence of the PHO2-POL3 (CDC2) region of chromosome IV of Saccharomyces cerevisiae. Yeast 10(12):1653-6
2) Mio T, et al.  (1998) The eukaryotic UDP-N-acetylglucosamine pyrophosphorylases. Gene cloning, protein expression, and catalytic mechanism. J Biol Chem 273(23):14392-7
3) Tkach JM, et al.  (2012) Dissecting DNA damage response pathways by analysing protein localization and abundance changes during DNA replication stress. Nat Cell Biol 14(9):966-76
4) Mengin-Lecreulx D and van Heijenoort J  (1993) Identification of the glmU gene encoding N-acetylglucosamine-1-phosphate uridyltransferase in Escherichia coli. J Bacteriol 175(19):6150-7
5) Mengin-Lecreulx D and van Heijenoort J  (1994) Copurification of glucosamine-1-phosphate acetyltransferase and N-acetylglucosamine-1-phosphate uridyltransferase activities of Escherichia coli: characterization of the glmU gene product as a bifunctional enzyme catalyzing two subsequent steps in the pathway for UDP-N-acetylglucosamine synthesis. J Bacteriol 176(18):5788-95
6) Cid VJ, et al.  (1995) Molecular basis of cell integrity and morphogenesis in Saccharomyces cerevisiae. Microbiol Rev 59(3):345-86