Biomaterial Database

[Hypoxanthine guanine phosphoribosyl transferase]. 1996

N Ogasawara

Institute for Developmental Research, Aichi Human Service Center.

The purine salvage enzyme hypoxanthine guanine phosphoribosyl transferase (HPRT) catalyzes the transfer of phosphoribose from PRPP to the 9-position of hypoxanthine or guanine, yielding IMP or GMP, respectively. HPRT is a 217-amino acid protein and is expressed in all tissues at low levels. High levels are present in brain, specially in the basal ganglia. HPRT is encoded by a single gene on the X chromosome (Xq26), which contains nine exons, dispersed over 40 kb of genomic DNA. mRNA is about 1.6 kb in length and contains an open reading frame of 654 nucleotides. Four autosomal pseudogenes are present within the human genome. The promoter sequences lack CAAT and TATAA elements and have an extremely CpG rich promoter. Hypomethylation of CpG clusters within the first intron and hypermethylation of sites within the 3' portion of the gene correlate with gene activity. Two DNA polymorphysms are located within the HPRT gene. One is a three-allele Bam HI restriction fragment-length polymorphysm and the other is a highly informative tetranucleotide(AGAT) tandem repeat located with intron 3.

UI	MeSH Term	Description	Entries
D007041	Hypoxanthine Phosphoribosyltransferase	An enzyme that catalyzes the conversion of 5-phosphoribosyl-1-pyrophosphate and hypoxanthine, guanine, or MERCAPTOPURINE to the corresponding 5'-mononucleotides and pyrophosphate. The enzyme is important in purine biosynthesis as well as central nervous system functions. Complete lack of enzyme activity is associated with the LESCH-NYHAN SYNDROME, while partial deficiency results in overproduction of uric acid. EC 2.4.2.8.	Guanine Phosphoribosyltransferase,HPRT,Hypoxanthine-Guanine Phosphoribosyltransferase,IMP Pyrophosphorylase,HGPRT,HPRTase,Hypoxanthine Guanine Phosphoribosyltransferase,Phosphoribosyltransferase, Guanine,Phosphoribosyltransferase, Hypoxanthine,Phosphoribosyltransferase, Hypoxanthine-Guanine,Pyrophosphorylase, IMP
D011110	Polymorphism, Genetic	The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.	Gene Polymorphism,Genetic Polymorphism,Polymorphism (Genetics),Genetic Polymorphisms,Gene Polymorphisms,Polymorphism, Gene,Polymorphisms (Genetics),Polymorphisms, Gene,Polymorphisms, Genetic
D011401	Promoter Regions, Genetic	DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.	rRNA Promoter,Early Promoters, Genetic,Late Promoters, Genetic,Middle Promoters, Genetic,Promoter Regions,Promoter, Genetic,Promotor Regions,Promotor, Genetic,Pseudopromoter, Genetic,Early Promoter, Genetic,Genetic Late Promoter,Genetic Middle Promoters,Genetic Promoter,Genetic Promoter Region,Genetic Promoter Regions,Genetic Promoters,Genetic Promotor,Genetic Promotors,Genetic Pseudopromoter,Genetic Pseudopromoters,Late Promoter, Genetic,Middle Promoter, Genetic,Promoter Region,Promoter Region, Genetic,Promoter, Genetic Early,Promoter, rRNA,Promoters, Genetic,Promoters, Genetic Middle,Promoters, rRNA,Promotor Region,Promotors, Genetic,Pseudopromoters, Genetic,Region, Genetic Promoter,Region, Promoter,Region, Promotor,Regions, Genetic Promoter,Regions, Promoter,Regions, Promotor,rRNA Promoters
D011685	Purine Nucleotides	Purines attached to a RIBOSE and a phosphate that can polymerize to form DNA and RNA.	Nucleotides, Purine
D012091	Repetitive Sequences, Nucleic Acid	Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).	DNA Repetitious Region,Direct Repeat,Genes, Selfish,Nucleic Acid Repetitive Sequences,Repetitive Region,Selfish DNA,Selfish Genes,DNA, Selfish,Repetitious Region, DNA,Repetitive Sequence,DNA Repetitious Regions,DNAs, Selfish,Direct Repeats,Gene, Selfish,Repeat, Direct,Repeats, Direct,Repetitious Regions, DNA,Repetitive Regions,Repetitive Sequences,Selfish DNAs,Selfish Gene
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012333	RNA, Messenger	RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.	Messenger RNA,Messenger RNA, Polyadenylated,Poly(A) Tail,Poly(A)+ RNA,Poly(A)+ mRNA,RNA, Messenger, Polyadenylated,RNA, Polyadenylated,mRNA,mRNA, Non-Polyadenylated,mRNA, Polyadenylated,Non-Polyadenylated mRNA,Poly(A) RNA,Polyadenylated mRNA,Non Polyadenylated mRNA,Polyadenylated Messenger RNA,Polyadenylated RNA,RNA, Polyadenylated Messenger,mRNA, Non Polyadenylated
D014960	X Chromosome	The female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in human and other male-heterogametic species.	Chromosome, X,Chromosomes, X,X Chromosomes