Linoleic acid controls neonatal tissue-specific stearoyl-CoA desaturase mRNA levels

The mouse genome contains two stearoyl-CoA desaturase (SCD) structural genes (SCD1 and SCD2) that are expressed in a tissue-specific manner. Brain SCD2 mRNA levels are about 2-fold higher in pups nursed by mothers fed a control diet (5% corn oil (CO), (essential fatty acid (EFA) adequate)), compared with brain SCD2 mRNA levels in pups nursed by mothers fed an EFA-deficient (EFAD) diet (5% coconut oil (COCO)). In contrast to brain, control pup hepatic SCD1 mRNA levels are reduced to < 1.0% of the EFAD pup hepatic SCD1 mRNA levels. EFA status does not alter SCD1 or SCD2 transcription initiation sites. CCAAT/enhancer-binding proteins (C/EBP) have been implicated in the transcriptional control of key genes in energy metabolism. Both the SCD1 and SCD2 gene promoters contain C/EBP transcription factor consensus-binding sites. Neonatal mouse liver expresses C/EBP-alpha, C/EBP-beta and C/EBP-delta mRNAs. In contrast neonatal mouse brain expresses high levels of C/EBP-delta, but little C/EBP-alpha or C/EBP-beta mRNA. EFA intake has no effect on tissue-specific C/EBP isoform mRNA levels suggesting that C/EBP isoform function is controlled at the translational or post-translational level.