The Longissimus and Semimembranosus Muscles Display Marked Differences in Their Gene Expression Profiles in Pig
et al. (2014) The Longissimus and Semimembranosus Muscles Display Marked Differences in Their
Gene Expression Profiles in Pig. PLoS ONE 9(5): e96491. doi:10.1371/journal.pone.0096491
The Longissimus and Semimembranosus Muscles Display Marked Differences in Their Gene Expression Profiles in Pig
Frederic Herault 0
Annie Vincent 0
Olivier Dameron 0
Pascale Le Roy 0
Pierre Cherel 0
Marie Damon 0
Dawit Tesfaye, University of Bonn, Germany
0 1 INRA, UMR1348, PEGASE , F-35590 Saint-Gilles, France, 2 Agrocampus Ouest, UMR1348, PEGASE, F-35000 Rennes, France, 3 Universite de Rennes1, F-35000 Rennes, France, 4 IRISA team Dyliss, F-35000 Rennes , France , 5 iBV-institut de Biologie Valrose, Universite Nice-Sophia Antipolis UMR CNRS 7277 Inserm U1091, Parc Valrose , F- 06108 Nice , France
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. Methodology/Principal Findings: 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/Significance: 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.
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Funding: This work was carried out with financial support from the ANR-Agence Nationale de la RechercheThe French National Research Agency under the
Programme National de Recherche en Alimentation, project ARN-PNRA-2006-25, GENMASCQ. The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Pork is one of the most widely eaten meats in the world.
Breeding programs aiming at improving pig production efficiency
through increased growth rate and lean meat content and
decreased fatness have also affected some meat quality traits
playing an important role in consumer acceptance of pork like
water holding capacity, color, intramuscular fat (IMF) content and
tenderness [1]. Meat quality is a complex trait which depends on
the interactive effects of pig genotype, environmental conditions,
pre-slaughter handling and slaughtering procedure [2]. The
skeletal muscle structure and metabolic characteristics which
determine cellular and molecular events occurring during muscle
to meat transformation are of the utmost importance for meat
quality determination. Skeletal muscle is a heterogeneous tissue
composed of myofibers, adipose, connective, vascular and nervous
tissues. Myofibers differ by their molecular, structural, contractile
and metabolic properties according to which they are classified as
slow-twitch oxidative (type I), fast-twitch oxido-glycolytic (type IIA)
and fast-twitch glycolytic (type IIB). Red or white muscles are also
determined according to their fiber type composition. Red muscles
are composed of high percentage of slow-twitch oxidative fibers
whereas white muscles contain a major proportion of fast-twitch
glycolytic fibers [3]. Longissimus and Semimembranosus - two white
skeletal muscles - are consumed in different forms: fresh for LM
(loin) or after processing for SM (ham). Both muscles are classified
as glycolytic even if slight differences have been described in their
myofiber composition (higher proportion of type IIa myofiber and
lower proportion of Type IIb myofiber in SM) and metabolic
properties (higher oxidative capacity in SM) [47]. Transcriptome
analysis might be useful to identify transcriptional signatures
associated with meat quality traits which could thus be selected as
biomarkers in selection programs [812]. However, pig
transcriptome studies are mainly focused on LM even if gen (...truncated)