Identification and expression of a rat fatty acid elongase involved in the biosynthesis of C18 fatty acids.
A major part of the palmitic acid (C16:0) generated by fatty acid synthase is converted into stearic acid (C18:0) via carbon chain elongation. Here, we describe the cloning and expression of a rat hepatic enzyme, rELO2, responsible for the elongation of C16:0, presumably at the condensing reaction. Heterologous expression experiments in a yeast, Saccharomyces cerevisiae, demonstrated the elongation activity of rELO2 on C16:0 and to a lesser extent, C18:0 and fatty acids with low desaturation degree. This was distinct from that rELO1, a rat homolog of HELO1, which preferably catalyzed the elongation of mono- and polyunsaturated fatty acids of C16-C20. The Northern analysis showed that the expression of rELO2, but not rELO1, in hepatocytes was activated by the cycles of fasting and refeeding rats on a fat-free diet. Under these conditions, the rELO1 was expressed constitutively in various tissues but the rELO2 transcripts were detected predominantly in liver.
Inagaki
Katsuya
K
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan.
Aki
Tsunehiro
T
Fukuda
Yoshihiro
Y
Kawamoto
Seiji
S
Shigeta
Seiko
S
Ono
Kazuhisa
K
Suzuki
Osamu
O
D000123:Acetyltransferases / Q000096:biosynthesis* / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004032:Diet; D005224:Fats, Unsaturated / Q000378:metabolism; D000081031:Fatty Acid Elongases; D005227:Fatty Acids / Q000032:analysis / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D015347:RNA Probes; D051381:Rats; D017207:Rats, Sprague-Dawley; D012441:Saccharomyces cerevisiae; D013379:Substrate Specificity; D014018:Tissue Distribution
D018076:DNA, Complementary; D005224:Fats, Unsaturated; D005227:Fatty Acids; D015347:RNA Probes; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases