TRANSDIFFERENTIATION OF CHICKEN EMBRYONIC-CELLS INTO MUSCLE-CELLS BY THE 3'-UNTRANSLATED REGION OF MUSCLE TROPOMYOSIN

Transfection with a plasmid encoding the 3' untranslated region (3' UT R) of skeletal muscle tropomyosin induces chicken embryonic fibroblast s to express skeletal tropomyosin. Such cells become spindle shaped, f use, and express titin, a marker of striated muscle differentiation. S keletal muscle tropomyosin and titin organize in sarcomeric arrays. Wh en the tropomyosin 3' UTR is expressed in osteoblasts, less skeletal m uscle tropomyosin is expressed, and titin expression is delayed. Some transfected osteoblasts become spindle shaped but do not fuse nor orga nize these proteins into sarcomeres. Transfected cells expressing musc le tropomyosin organize muscle acid nonmuscle isoforms into the same s tructures. Thus, the skeletal muscle tropomyosin 3' UTR induces transd ifferentiation into a striated muscle phenotype in a cell-type-specifi c context.