Genomic structure, chromosomal mapping, and promoter region analysis of murine uridine phosphorylase gene.
Uridine phosphorylase (UPase) plays an important role in the activation of 5-fluorouracil and in the regulation of tissue and plasma concentration of uridine, a potential biochemical modulator of 5-fluorouracil therapy. UPase expression is affected by the c-H-ras oncogene and various cytokines through unknown mechanisms. To understand its expression and regulation, we cloned the murine UPase gene, defined its genomic organization, determined its 5'- and 3'-end flanking sequences, and evaluated the promoter activity. The UPase gene contains nine exons and eight introns, spanning a total of approximately 18.0 kb. Its promoter lacks canonical TATA and CCAAT boxes, although a CAATAAAAA TATA-like box is seen from -41 to -49. Furthermore, IFN regulatory factor 1, c/v-Myb, and p53 binding sites are present in the promoter region, indicating that UPase expression may be directly regulated by cytokines and oncogene products. The 1.2-kb flanking fragment showed promoter activity driving the expression of the luciferase gene in various mammalian cells. A TGGGG repeat sequence is seen in the 3'-end flanking region. This element is considered to be a potential recombination consensus hot spot that may contribute to the encoding of different UPase isoforms present in different tissues, both normal and neoplastic.
Cao
D
D
Department of Internal Medicine (Oncology), Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Nimmakayalu
M A
MA
Wang
F
F
Zhang
D
D
Handschumacher
R E
RE
Bray-Ward
P
P
Pizzorno
G
G
D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D005091:Exons; D015971:Gene Expression Regulation, Enzymologic; D007438:Introns; D007621:Karyotyping; D008214:Lymphocytes / Q000201:enzymology; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D013154:Spleen / Q000201:enzymology; D014543:Uridine Phosphorylase / Q000235:genetics*
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D004268:DNA-Binding Proteins; D014543:Uridine Phosphorylase