Schematic model showing the links between the significant changes of muscle-specific attributes with the expression of ERV env genes, their receptors and muscle specific genes relating to cell fusion occurring <i>in vivo</i> (biopsies from cyclists at the pre- and post- competitive seasons) and <i>in vitro</i>. Sebastian Frese Matthias Ruebner Frank Suhr Thierry M. Konou Kim A. Tappe Marco Toigo Hans H. Jung Christine Henke Ruth Steigleder Pamela L. Strissel Hanna Huebner Matthias W. Beckmann Piet van der Keylen Benedikt Schoser Thorsten Schiffer Laura Frese Wilhelm Bloch Reiner Strick 10.1371/journal.pone.0132099.g008 https://plos.figshare.com/articles/figure/_Schematic_model_showing_the_links_between_the_significant_changes_of_muscle_specific_attributes_with_the_expression_of_ERV_env_genes_their_receptors_and_muscle_specific_genes_relating_to_cell_fusion_occurring_in_vivo_biopsies_from_cyclists_at_the_pre_and/1477102 <p>The top represents the muscle differentiation in cyclists from pre- (PRE) to post-competitive season (POST), whereas the bottom symbolizes the myoblast cultures proliferating in growth media (GM) or differentiating to myotubes in differentiation media (DM). Additionally, since SCs and myonuclei showed positive expression for protein kinase A activated pCREB-Ser133 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132099#pone.0132099.g004" target="_blank">Fig 4</a>) and treatment of primary myoblast cultures with the cAMP stimulator Forskolin did not promote myoblast cell fusion (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0132099#pone.0132099.g006" target="_blank">Fig 6</a>), we predict that cAMP may be important for regulating SCs. SC = satellite cells; MP = muscle progenitors; MT = myotubes; PRE = pre-competition; POST = post-competition; GM = growth media; DM = differentiation media; arrow up = significantly up-regulated and arrow down = significantly down-regulated.</p> 2015-07-08 02:50:46 cell fusion Erv 3 protein PAX 7 gene regulations biopsy rxr ERV envelope proteins muscle biopsies syncytin Cellular receptors SLC 1A SC nuclei myoblast cell cultures Other cell fusion events Fusogenic Endogenous Retroviral Genes SLC 1A protein expression bone resorbing osteoclasts ppar myofiber envelope genes