Role of a New Mammalian Gene Family in the Biosynthesis of Very Long Chain Fatty Acids and Sphingolipids

• Published in: The Journal of cell biology 2000-05, Vol.149 (3), p.707-717
• Main Authors: Tvrdik, Petr, Westerberg, Rolf, Silve, Sandra, Asadi, Abolfazl, Jakobsson, Andreas, Cannon, Barbara, Loison, Gerard, Jacobsson, Anders
• Format: Article
• Language: English
• Subjects: Acetyltransferases; Adipose Tissue, Brown - metabolism; Amino Acid Sequence; Animals; Base Sequence; Brown adipose tissue; Cell membranes; cerotic acid; Cig30 gene; Cloning, Molecular; Down-Regulation; elo2 gene; elo3 gene; Enzymes; Fatty acids; Fatty Acids - biosynthesis; fen1 gene; Genes; Genetic Complementation Test; Lipids; Mammals; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membranes; Messenger RNA; Mice; Mice, Jimpy; Mice, Quaking; Microsomes - metabolism; Molecular Sequence Data; Mutation; Myelin Sheath - genetics; Original; RNA; RNA, Messenger - metabolism; Saccharomyces cerevisiae; Sequence Alignment; Sphingolipids; Sphingolipids - biosynthesis; Ssc1 gene; Ssc2 gene; sur4 gene; Yeasts; Yeasts - genetics
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.149.3.707

Whereas the physiological significance of microsomal fatty acid elongation is generally appreciated, its molecular nature is poorly understood. Here, we describe tissue-specific regulation of a novel mouse gene family encoding components implicated in the synthesis of very long chain fatty acids. The Ssc1 gene appears to be ubiquitously expressed, whereas Ssc2 and Cig30 show a restricted expression pattern. Their translation products are all integral membrane proteins with five putative transmembrane domains. By complementing the homologous yeast mutants, we found that Ssc1 could rescue normal sphingolipid synthesis in the sur4/elo3 mutant lacking the ability to synthesize cerotic acid ( C26: 0). Similarly, Cig30 reverted the phenotype of the fen1/elo2 mutant that has reduced levels of fatty acids in the C20- C24range. Further, we show that Ssc1 mRNA levels were markedly decreased in the brains of myelin-deficient mouse mutants known to have very low fatty acid chain elongation activity. Conversely, the dramatic induction of Cig30 expression during brown fat recruitment coincided with elevated elongation activity. Our results strongly implicate this new mammalian gene family in tissue-specific synthesis of very long chain fatty acids and sphingolipids.