CLONING OF DNA COMPLEMENTARY TO RAT-LIVER FATTY-ACID SYNTHETASE MESSENGER-RNA

Clones, containing DNA complementary (cDNA) to rat liver fatty acid synthetase mRNA, were constructed and identified. cDNA of these clones was then used as a probe to quantify mRNA. The cDNA was synthesized to partially purified rat liver fatty acid synthetase mRNA. Double-stranded cDNA was then prepared and inserted into the PstI site of pBR322 using oligo(dG) X oligo(dC) tailing. Initial selection of the clones was by differential colony hybridization employing [32P]cDNA synthesized from poly(A)-rich mRNA, enriched and non-enriched in fatty acid synthetase mRNA, as probes. Plasmids, containing specific sequences complementary to the fatty acid synthetase mRNA, were identified by hybrid-arrest translation. Cloned cDNA inserts ranged from 300 to 1400 base pairs. Cloned cDNA was employed to probe for mRNA in hybridizations via the dot-blot method. These studies demonstrated an increase in fatty acid synthetase mRNA during dietary induction, which suggests that regulation may involve changes in transcription or changes in post-transcriptional processing of the mRNA.