A 27-mer oligonucleotide probe for the detection and measurement of the mRNA for uncoupling protein in brown adipose tissue of different species.

1. Data from rats, cattle, mice, rabbits and humans indicate considerable species heterogeneity in the sequence of the gene coding for the mitochondrial uncoupling protein (UCP) in brown adipose tissue. A 27-base sequence of an exon region of the gene is, however, identical in rats and cattle; in mice, rabbits, and humans this same region shows only a single base difference from the sequence in rats and cattle. 2. A 27-mer oligonucleotide (3'-TGGAAGGGCGACCTGTGGCGGTTTCAG-5') complementary to the conserved region of the rat and cattle UCP genes has been synthesized as a potential probe for UCP mRNA in widely differing species. 3. Northern blots of RNA from rat brown fat showed that the oligonucleotide hybridized with a 1.5 kbase mRNA, indicative of UCP mRNA. No hybridization was observed with RNA from white fat (subcutaneous, internal), liver, kidney, skeletal muscle, heart and brain. Acute cold-exposure of rats and mice led to an increase in UCP mRNA level, while streptozotocin-induced diabetes resulted in a decrease. 4. The oligonucleotide hybridized with a 1.5 (or 1.9) kbase mRNA from brown fat of rats, mice, golden hamsters, Djungarian hamsters, and newborn rabbits, pipistrelle bats, lambs, goats and red deer. 5. The 27-mer oligonucleotide provides a simple probe for UCP mRNA across a wide range of mammals, obviating any need to obtain species-specific cDNAs.