Comparative anatomy of the human APRT gene and enzyme: nucleotide sequence divergence and conservation of a nonrandom CpG dinucleotide arrangement

Journal Article · Fri May 01 04:00:00 EDT 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.10.3349· OSTI ID:5561972

Broderick, T P; Schaff, D A; Bertino, A M; Dush, M K; Tischfield, J A; Stambrook, P J

The functional human adenine phosphoribosyltransferase (APRT) gene is <2.6 kilobases in length and contains five exons. The amino acid sequences of APRTs have been highly conserved throughout evolution. The human enzyme is 82%, 90%, and 40% identical to the mouse, hamster, and Escherichia coli enzymes, respectively. The promoter region of the human APRT gene, like that of several other housekeeping genes, lacks TATA and CCAAT boxes but contains five GC boxes that are potential binding sites for the Sp1 transcription factor. The distal three, however, are dispensable for gene expression. Comparison between human and mouse APRT gene nucleotide sequences reveals a high degree of homology within protein coding regions but an absence of significant homology in 5' flanking, 3' untranslated, and intron sequences, except for similarly positioned GC boxes in the promoter region and a 26-base-pair region in intron 3. This 26-base-pair sequence is 92% identical with a similarly positioned sequence in the mouse gene and is also found in intron 3 of the hamster gene, suggesting that its retention may be a consequence of stringent selection. The positions of all introns have been precisely retained in the human and both rodent genes. Retention of an elevated CpG dinucleotide content, despite loss of sequence homology, suggests that there may be selection for CpG dinucleotides in these regions and that their maintenance may be important for APRT gene function.

• Research Organization: Univ. of Cincinnati College of Medicine, OH
• OSTI ID: 5561972
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 84:10; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
BACTERIA
BACTERIOPHAGES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EVOLUTION
DAYS LIVING RADIOISOTOPES
DNA
DNA SEQUENCING
ENZYMES
ESCHERICHIA COLI
GENES
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
MOLECULAR STRUCTURE
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PARASITES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
RADIOISOTOPES
RECOMBINANT DNA
STRUCTURAL CHEMICAL ANALYSIS
TRANSFERASES
VIRUSES