STEAROYL-COA DESATURASE MESSENGER-RNA IS TRANSCRIBED FROM A SINGLE-GENE IN THE OVINE GENOME

Clones corresponding to ovine stearoyl-CoA desaturase (SCD) cDNA were isolated from an adipose tissue cDNA library. All of these clones repr esented a single mRNA species as judged by restriction fragment and DN A sequence analysis. RNase protection analysis demonstrated that this SCD transcript is highly expressed in adipose tissue and liver, and in the mammary gland of lactating animals. A lower level of expression w as detectable in a variety of other tissues including brain. Levels of the SCD transcript were decreased in adipose tissue during lactation, and this appears to be related to a marked decline in serum insulin a nd insulin-responsiveness of the tissue. Southern analysis of ovine an d mouse genomic DNA demonstrated that the ovine SCD cDNA hybridised in a manner consistent with a single gene for SCD in ovine DNA; mouse ge nomic DNA produced a pattern of hybridisation consistent with the prev iously characterised mouse SCD-1 and SCD-2 genes, Three ovine cosmids were isolated that comprised the restriction fragments predicted by th e genomic Southern analysis. The ovine SCD gene was predicted to be en compassed within a 23 kbp region that was present in all three cosmids . These results demonstrate that SCD is transcribed from a single gene in the ovine genome and this gene is insulin-responsive in ovine adip ose tissue. (C) 1998 Elsevier Science B.V.