title: The Longissimus and Semimembranosus muscles display marked differences in their gene expression profiles in pig.
abstract: BACKGROUND
  Meat quality depends on skeletal muscle structure and metabolic properties. While most studies carried on pigs focus on the Longissimus muscle (LM) for fresh meat consumption, Semimembranosus (SM) is also of interest because of its importance for cooked ham production. Even if both muscles are classified as glycolytic muscles, they exhibit dissimilar myofiber composition and metabolic characteristics. The comparison of LM and SM transcriptome profiles undertaken in this study may thus clarify the biological events underlying their phenotypic differences which might influence several meat quality traits.
  
  
  RESULTS
  Muscular transcriptome analyses were performed using a custom pig muscle microarray: the 15 K Genmascqchip. A total of 3823 genes were differentially expressed between the two muscles (Benjamini-Hochberg adjusted P value ≤0.05), out of which 1690 and 2133 were overrepresented in LM and SM respectively. The microarray data were validated using the expression level of seven differentially expressed genes quantified by real-time RT-PCR. A set of 1047 differentially expressed genes with a muscle fold change ratio above 1.5 was used for functional characterization. Functional annotation emphasized five main clusters associated to transcriptome muscle differences. These five clusters were related to energy metabolism, cell cycle, gene expression, anatomical structure development and signal transduction/immune response.
  
  
  CONCLUSIONS
  This study revealed strong transcriptome differences between LM and SM. These results suggest that skeletal muscle discrepancies might arise essentially from different post-natal myogenic activities.
authors.affiliation: INRA, UMR1348, PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348, PEGASE, F-35000 Rennes, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Herault
authors.affiliation: INRA, UMR1348, PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348, PEGASE, F-35000 Rennes, France.
authors.forename: Annie
authors.initials: A
authors.lastname: Vincent
authors.affiliation: Université de Rennes1, F-35000 Rennes, France; IRISA team Dyliss, F-35000 Rennes, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Dameron
authors.affiliation: INRA, UMR1348, PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348, PEGASE, F-35000 Rennes, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Le Roy
authors.affiliation: iBV-institut de Biologie Valrose, Université Nice-Sophia Antipolis UMR CNRS 7277 Inserm U1091, Parc Valrose, F-06108 Nice, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Cherel
authors.affiliation: INRA, UMR1348, PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348, PEGASE, F-35000 Rennes, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Damon
mesh_terms: D000818:Animals; D020869:Gene Expression Profiling; D008460:Meat; D018482:Muscle, Skeletal / Q000378:metabolism*; D034421:Sus scrofa / Q000235:genetics* / Q000378:metabolism; D013552:Swine; D046888:Tissue Array Analysis; D059467:Transcriptome