1-Acyl-sn-glycerol-3-phosphate (1-AGP), also known as lysophosphatidic acid (LPA), is an intermediate of de novo biosynthesis of glycerophospholipids and triacylglycerol. LPA is also attracting much attention because of its growth stimulating effects. Here we report cloning of murine cDNA encoding 1-AGP acyltransferase (1-AGPAT), which converts LPA into phosphatidic acid by incorporating acyl moiety at an-2 position. The cDNA contains an open reading frame coding for 285 amino acids, with highly hydrophobic regions in the N-terminal half. The Northern blot analysis using various mouse tissues revealed ubiquitous expressions of two transcripts. The cDNA was expressed in Escherichia coli JC201, a plsC mutant strain deficient in the 1-AGPAT activity, and the enzyme properties were examined. The enzyme utilized both saturated and unsaturated acyl-CoA as an acyl-donor, while it utilized LPA but not other lysophospholipids as an acceptor.