Nesprin 1 is critical for nuclear positioning and anchorage.

Nesprin 1 is an outer nuclear membrane protein that is thought to link the nucleus to the actin cytoskeleton. Recent data suggest that mutations in Nesprin 1 may also be involved in the pathogenesis of Emery-Dreifuss muscular dystrophy. To investigate the function of Nesprin 1 in vivo, we generated a mouse model in which all isoforms of Nesprin 1 containing the C-terminal spectrin-repeat region with or without KASH domain were ablated.

Progressive myopathy and defects in the maintenance of myotendinous junctions in mice that lack talin 1 in skeletal muscle.

The development and function of skeletal muscle depend on molecules that connect the muscle fiber cytoskeleton to the extracellular matrix (ECM). beta1 integrins are ECM receptors in skeletal muscle, and mutations that affect the alpha7beta1 integrin cause myopathy in humans. In mice, beta1 integrins control myoblast fusion, the assembly of the muscle fiber cytoskeleton, and the maintenance of myotendinous junctions (MTJs).

Sarcomere length measurement permits high resolution normalization of muscle fiber length in architectural studies.

The use of sarcomere length to normalize fiber length in architectural studies is commonly practiced but has not been explicitly validated. Using mouse hindlimb muscles as a model system, ankle joints were intentionally set to angles ranging from 30 degrees to 150 degrees and their muscles fixed. Tibialis anterior (TA), extensor digitorum longus (EDL) and soleus muscles were removed and their raw fiber length measured.