Phenotype Image Detail

Image

Caption

Six1 expression by satellite cells is necessary for proper skeletal muscle regeneration. Three days after tamoxifen treatment, tibialis anterior (TA) muscles of control and Six1^tm2.1Mair/Six1^tm2.1Mair Pax7^{tm1(cre/ERT2)Gaka}/Pax7⁺ (Six1KO) mice were injured by a single CTX injection and analyzed at various times during the regeneration process. (B) Cryosections of 4 day regenerating TA muscles. Immunolocalization of myosin heavy chain embryonic (MyHC emb) proteins marks the newly formed myofibers. Regenerating myofibers of mutants are smaller compared with controls and contain fewer nuclei. (E) Cryosections of 7 day regenerating TA muscles. Laminin staining shows basal lamina of myofibers. Strong MyHC embryonic staining marks a population of small, delayed myofibers. (H) Cryosections of regenerated TA muscles 14 days after cardiotoxin (CTX) injection. Laminin staining shows basal lamina of myofibers. Note the abnormal accumulation of matrix in mutant muscles. Regenerated mutant muscles contain smaller fibers compared with regenarated control muscles. (J) Cryosections of regenerated TA muscles 14 days after CTX injection. Dystrophin staining shows myofibers sarcolemma. Shown is the percentage of Six1⁺ myonuclei. Regeneration of the muscle tissue results in a higher number of nuclei per myofiber on cross sections in controls but not in mutant animals. Bars, 50 um.

Copyright

This image is from Le Grand F, J Cell Biol 2012 Sep 3;198(5):815-32, and is displayed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. J:190460

Associated Alleles

Symbol	Name
Pax7^tm1(cre/ERT2)Gaka	paired box 7; targeted mutation 1, Gabrielle Kardon
Six1^tm2.1Mair	sine oculis-related homeobox 1; targeted mutation 2.1, Pascal Maire

Associated Genotypes

Allelic Composition	Genetic Background
Six1^tm2.1Mair/Six1^tm2.1Mair Pax7^tm1(cre/ERT2)Gaka/Pax7^+	involves: 129S6/SvEvTac * C57BL/6 * C57BL/6Cr * C57BL/6NTac