File:Muscle- C2C12 differentiation.jpg

Time course of C2C12 differentiation

(A) C2C12 cells were placed in differentiation medium when culture reached 80% of confluence (t = 0 h). After 48 hours, the first myotubes, indicated by arrows, had clearly formed and after 11 days (t = 264 h), most of the cells had merged into myotubes.

(B) C2C12 RNA was extracted at several differentiation time points and tested for the presence of mRNA from the myogenic markers Myf5, MyoD, Myogenin and Mrf4.

(C) mRNA from the muscle-specific markers Csrp3, Hes6, Mef2a and Mef2d. Transcription levels are expressed as relative quantities (RQ) compared to the initiation of differentiation (t = 0 h). The grey area includes no significant variations (RQ < ± 2). For (B), standard deviations were calculated on three separate experimental values.

• No significant transcriptional expression of Mrf4 was detected before t = 192 h (Ct>33, dotted line).
• The top inset presents the standard expression patterns of the four myogenic markers Myf5, MyoD, Myogenin and Mrf4 as found in the literature.

Original file name: Figure 1. 1471-2164-10-483-1.jpg http://www.biomedcentral.com/1471-2164/10/483/figure/F1

Janot et al. BMC Genomics 2009 10:483 doi:10.1186/1471-2164-10-483

"BACKGROUND: Several global transcriptomic and proteomic approaches have been applied in order to obtain new molecular insights on skeletal myogenesis, but none has generated any specific data on glycogenome expression, and thus on the role of glycan structures in this process, despite the involvement of glycoconjugates in various biological events including differentiation and development. In the present study, a quantitative real-time RT-PCR technology was used to profile the dynamic expression of 375 glycogenes during the differentiation of C2C12 myoblasts into myotubes.

RESULTS: Of the 276 genes expressed, 95 exhibited altered mRNA expression when C2C12 cells differentiated and 37 displayed more than 4-fold up- or down-regulations. Principal Component Analysis and Hierarchical Component Analysis of the expression dynamics identified three groups of coordinately and sequentially regulated genes. The first group included 12 down-regulated genes, the second group four genes with an expression peak at 24 h of differentiation, and the last 21 up-regulated genes. These genes mainly encode cell adhesion molecules and key enzymes involved in the biosynthesis of glycosaminoglycans and glycolipids (neolactoseries, lactoseries and ganglioseries), providing a clearer indication of how the plasma membrane and extracellular matrix may be modified prior to cell fusion. In particular, an increase in the quantity of ganglioside GM3 at the cell surface of myoblasts is suggestive of its potential role during the initial steps of myogenic differentiation.

CONCLUSION: For the first time, these results provide a broad description of the expression dynamics of glycogenes during C2C12 differentiation. Among the 37 highly deregulated glycogenes, 29 had never been associated with myogenesis. Their biological functions suggest new roles for glycans in skeletal myogenesis."

Reference

<pubmed>19843320</pubmed>| PMC2772862 | BMC Genomics

© 2009 Janot et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.