CLONING AND EXPRESSION OF FULL-LENGTH MOUSE UTROPHIN - THE DIFFERENTIAL ASSOCIATION OF UTROPHIN AND DYSTROPHIN WITH ACHR CLUSTERS

We have cloned and sequenced mouse utrophin cDNA, and successfully exp ressed full length utrophin (400 kDa) in both muscle and non-muscle ce lls. The expression of recombinant utrophin is compared with that of i ts homologue, dystrophin (427 kDa). We demonstrate that recombinant ut rophin is targeted into agrin-induced acetylcholine receptor (AChR) cl usters, while recombinant dystrophin is evenly distributed along cell membranes in cultured Sol 8 muscle cells. This observation suggests th at utrophin and dystrophin may interact with different cytoskeletal pr oteins. The C-terminal domains are found to be responsible for the ass ociation of utrophin with AChR clusters.