Isolation and analysis of a rat genomic clone containing a long terminal repeat with high similarity to the oncomodulin mRNA leader sequence.
The structure of a novel long terminal repeat (LTR) from an intracisternal A particle (IAP) DNA element in the rat (Sprague-Dawley) genome was determined. This LTR has a total length of 313 base pairs (bp). Several structural features typical for retroviral LTR promoters were identified, including a "CCAAT" box, a "TATA" box, a polyadenylation signal, and a polyadenylation site. The LTR is flanked by 3-bp inverted repeats, and it consists of the three typical LTR regions, U3, R, and U5. U3 contains 213 bp, R 46 bp, and U5 54 bp, which is within the usual size range of IAP LTRs. A sequence of 60 bp in the U3 region reveals considerable similarity to a murine IAP LTR U3 element, which is known to interact with nuclear proteins. A sequence of 69 bp in the U5 and R regions has 83 and 93% similarities to an endogenous retroviral LTR from Syrian hamster and to the cDNA leader sequence of (Buffalo) rat oncomodulin, respectively. Oncomodulin is an "EF-hand" Ca2+-binding protein and appears in many human and rodent tumors and in cells with tumor-like properties but not in normal tissues. We postulate that in the rat the tumor-specific expression of oncomodulin is controlled by a retroviral LTR promoter.
Furter
C S
CS
Institute of Pharmacology and Biochemistry, University of Zurich-Irchel, Switzerland.
Heizmann
C W
CW
Berchtold
M W
MW
D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000235:genetics*; D006224:Cricetinae; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015342:DNA Probes; D004274:DNA, Recombinant / Q000302:isolation & purification; D008647:Mesocricetus; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009693:Nucleic Acid Hybridization; D011401:Promoter Regions, Genetic / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics
D002135:Calcium-Binding Proteins; D015342:DNA Probes; D004274:DNA, Recombinant; D009363:Neoplasm Proteins; C034733:oncomodulin; D004247:DNA