Integrin expression patterns during early limb muscle development in the mouse

Cell-extracellular matrix interactions play crucial roles in limb muscle development but practically nothing is known on what integrins are involved before the differentiation of muscle precursor cells ( MPCs) in the limb muscle masses. In this study we determine the expression patterns of integrins during early forelimb muscle development in the mouse. alpha 6 beta 1 integrin is downregulated in the lateral dermomyotome when delamination of MPCs occurs. In late E9.5 embryos, alpha 1 beta 1 and alpha 5 beta 1 are expressed in a pattern very similar to pax3, which marks MPCs migrating to the limb bud. After myf5 upregulation in the limb bud, alpha 1 beta 1 and alpha 5 beta 1 expression is maintained and the alpha 4 beta 1 integrin starts being expressed. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.