The TAG1 locus of Arabidopsis encodes for a diacylglycerol acyltransferase

Diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) is a membrane enzyme tha t drives the final step in the formation of oils using diacylglycerol (DAG) and acyl-CoA to yield triacylglycerol (TAG). We identified a putative plan t DGAT gene (TRIACYLGLYCEROL1: TAG1) and demonstrated its function by the c loning of two mutated alleles, designated AS11 (tag1-1) and ABX45 (tag1-2). One allele, AS11, has been previously characterised at the biochemical lev el. Mutant seeds contained less oil with a modified fatty acid profile and have reduced germination rates compared to wild-type controls. The TAG1 cDN A encodes for a 520-aa protein that possesses multiple putative transmembra ne domains and shows 70 % similarity to a human DGAT cDNA. (C) 1999 Edition s scientifiques et medicales Elsevier SAS.