Transcriptome Expression Profiles in Prenatal Pigs in Relation to Myogenesis

Abstract

Myogenesis, the formation of muscle fibers, is a complex process. Pigs have been selected for efficient muscle growth for the past decades making them interesting to study myogenesis. We studied expression profiles of genes known to affect myogenesis, muscle structural proteins, and energy metabolism in prenatal pigs from 14 to 91 days of gestation. Primary and secondary muscle fiber formation takes place during days 30-60 and 54-90 of gestation, respectively. Differential expression and expression levels of the genes were studied using microarray technology. Gene activation and repression profiles were studied counting the number of spots with detectable signal. The number of spots for muscle tissue structural protein genes showing upregulated expression increased constantly from day 14 until day 91of gestation indicating continued activation of genes during this period. The mRNA expression level of the genes showed a peak around day 35 of gestation. The expression levels of genes affecting myogenic differentiation (stimulating and inhibiting) showed a peak at day 35 of gestation. The number of spots for differentiation-stimulating genes showing differential expression reaches a first peak around day 35 of gestation and a nadir at day 49 of gestation while the number of spots for differentiation-inhibiting genes reaches a nadir at day 35 of gestation. Myogenic differentiation seems less a matter of the expression level of genes affecting differentiation, but depends on the balance between the number of significantly activated genes for stimulating and inhibiting differentiation. Genes stimulating myoblast proliferation showed a small peak expression prior to day 35 of gestation indicating myoblast proliferation before differentiation. The number of spots and the expression levels of genes for glycolysis and ATP-metabolism are at a nadir around days 35 and 49-63 of gestation suggesting that the energy metabolism is low during fusion of myoblasts into multinucleated muscle fibers.

Invited review: Measurable biomarkers linked to meat quality from different pig production systems

“…We studied the transcriptome expression in porcine longissimus dorsi muscles of Duroc pigs. The results showed that especially the primary wave of prenatal muscle fibre formation is strongly genetically regulated, while the secondary muscle fibre formation is associated with much less differential gene expression (te Pas et al, 2005;Cagnazzo et al, 2006). This is in agreement with the fact that the secondary muscle fibre formation can be regulated with feed, while the primary muscle fibre formation cannot be affected Stickland et al, 2004;reviewed in Rehfeldt et al, 2011a, b).…”

“…Interestingly, the number of differently expressed genes for energy metabolism suggest that proliferation of myoblasts prior to differentiation is accompanied by oxidative phosphorylation, while during differentiation (i.e. fusion into multinucleated muscle fibres) glycolysis seems to be of main importance (te Pas et al, 2005).…”

Analysis of mRNA expression of CNN3, DCN, FBN2, POSTN, SPARC and YWHAQ genes in porcine foetal and adult skeletal muscles

“…The mean relative ratios were approximately Expression analyses of muscle genes in different pig breeds and different developmental stages showed to be very useful both to improve gene maps and to increase the number of candidate genes that could be involved in controlling production traits (Wimmers et al, 2004). The macro-and microarray technologies were used to simultaneously measure the expression of a large number of genes in different developmental stages of embryonic/fetal development and in postnatal muscle, as well as to study differences in expression between different breeds of pigs (te Pas et al, 2005;Cagnazzo et al, 2006;Wimmers et al, 2007). It was shown that some genes are down regulated, others up regulated, and some do not change their expression level.…”

“…Davoli et al, 2002; te Pas et al, 2005;Cagnazzo et al, 2006). Many of the genes were mapped (Davoli et al, 2002) and some of them were used as functional or positional candidates for association studies with meat quality and carcass traits (Wimmers et al, 2007) or for QTL mapping .…”

Molecular cloning of the duck MyoG and MRF4 genes coding region sequence and their differential expression patterns in the breast and leg muscle during fetal development

“…Murine tongue muscle displays a distinct developmental profile of MRF gene expression compared with other muscles (Dalrymple et al 1999;Yamane et al 2000). In recent years, MRFs expression profile has been proven to vary among the muscles of different origins (Te Pas et al 2005) and among the different muscle fiber types. Muscle fibers can be divided into two types: redder muscle fiber types and whiter muscle fiber types.…”