Combined cDNA array/RT-PCR analysis of gene expression profile in rat gastrocnemius muscle: relation to its adaptive function in energy metabolism during fasting.
We evaluated the effects of fasting on the gene expression profile in rat gastrocnemius muscle using a combined cDNA array and RT-PCR approach. Of the 1176 distinct rat genes analyzed on the cDNA array, 114 were up-regulated more than twofold in response to fasting, including all 17 genes related to lipid metabolism present on the membranes and all 10 analyzed components of the proteasome machinery. Only 7 genes were down-regulated more than twofold. On the basis of our analysis of genes on the cDNA array plus the data from our RT-PCR assays, the metabolic adaptations shown by rat gastrocnemius muscle during fasting are reflected by i) increased transcription both of myosin heavy chain (MHC) Ib (associated with type I fibers) and of at least three factors involved in the shift toward type I fibers [p27kip1, muscle LIM protein (MLP), cystein rich protein-2], of which one (MLP) has been shown to enhance the activity of MyoD, which would explain the known increase in the expression of skeletal muscle uncoupling protein-3 (UCP3); ii) increased lipoprotein lipase (LPL) expression, known to trigger UCP3 transcription, which tends, together with the first point, to underline the suggested role of UCP3 in mitochondrial lipid handling (the variations under the first point and this one have not been observed in mice, indicating a species-specific regulation of these mechanisms); iii) reduced expression of the muscle-specific coenzyme Q (CoQ)7 gene, which is necessary for mitochondrial CoQ synthesis, together with an increased expression of mitochondrial adenylate kinase 3, which inactivates the resident key enzyme for CoQ synthesis, 3-hydroxy-3-methylglutaryl CoA reductase (HMGR), the mRNA level for which fell during fasting; and iv) increased transcription of components of the proteasomal pathways involved in protein degradation/turnover.
de Lange
Pieter
P
Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli (SUN), Caserta, Italy.pieter.delange@unina2.it
Ragni
Maurizio
M
Silvestri
Elena
E
Moreno
Maria
M
Schiavo
Luigi
L
Lombardi
Assunta
A
Farina
Paola
P
Feola
Anna
A
Goglia
Fernando
F
Lanni
Antonia
A
D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D004734:Energy Metabolism; D005215:Fasting; D016166:Free Radical Scavengers / Q000378:metabolism; D020869:Gene Expression Profiling; D006360:Heat-Shock Proteins / Q000235:genetics; D050356:Lipid Metabolism; D008928:Mitochondria / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch; D018482:Muscle, Skeletal / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010085:Oxidative Phosphorylation; D011494:Protein Kinases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011972:Receptor, Insulin / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics; D047888:Receptors, Tumor Necrosis Factor, Type I; D047488:Retinoid X Receptors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics; D014451:Ubiquinone / Q000096:biosynthesis; D025801:Ubiquitin / Q000235:genetics; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics
D015703:Antigens, CD; D016166:Free Radical Scavengers; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047488:Retinoid X Receptors; D014157:Transcription Factors; D025801:Ubiquitin; D014451:Ubiquinone; D044763:Ubiquitin-Conjugating Enzymes; D011494:Protein Kinases; D011972:Receptor, Insulin; D018995:Myosin Heavy Chains