Molecular cloning and characterization of the sheep malic enzyme cDNA.
Malic enzyme catalyzes decarboxylation of malate to pyruvate and CO(2), providing de novo biosynthesis of fatty acids with NADPH. Since lipogenesis in ruminants, contrarily to some monogastric species like human and rodents, occurs predominantly in adipose tissue, the activity of many lipogenic enzymes is higher in adipose tissue compared to liver. Expression of malic enzyme is regulated by nutrition; refeeding after a period of starvation results to an induction of the enzyme. Here we present the nucleotide sequence of two transcripts of the ovine cytosolic malic enzyme gene that differ at the length of the 3' UTR. These are the first published cDNA sequences for ruminant species and share high similarity with the corresponding sequences of other species. Malic enzyme mRNA was present in every ovine tissue that was examined. In agreement with the fact that adipose tissue is the major lipogenic site for ruminants, mRNA levels in adipose tissue were higher than in liver. Refeeding after two weeks of caloric restriction resulted in a two-fold increase of the mRNA level of malic enzyme in adipose tissue.
Stefos
Georgios C
GC
Department of Animal Science, Laboratory of Animal Breeding and Husbandry, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece.
Argyrokastritis
Alexandros
A
Bizelis
Iosif
I
Rogdakis
Emmanuel
E
D000273:Adipose Tissue / Q000201:enzymology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D008291:Malate Dehydrogenase / Q000737:chemistry / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012756:Sheep / Q000235:genetics* / Q000378:metabolism; D013217:Starvation / Q000201:enzymology / Q000235:genetics; D014018:Tissue Distribution
D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D008291:Malate Dehydrogenase