Delineation of a slow-twitch-myofiber-specific transcriptional element by using in vivo somatic gene transfer.

摘要: Abstract Contractile proteins are encoded by multigene families, most of whose members differentially expressed in fast- versus slow-twitch myofibers. This fiber-type-specific gene regulation occurs unknown mechanisms and does not occur within cultured myocytes. We have developed a transient, whole-animal assay using somatic transfer to study this phenomenon identified regulatory element the promoter region slow myofiber-specific gene. A plasmid-borne luciferase reporter fused various muscle-specific contractile promoters was when injected into slow- fast-twitch rat muscle: preferentially muscle troponin I promoter, conversely, fast C promoter. In contrast, equally well both types nonfiber-type-specific skeletal actin Deletion analysis revealed that 157-bp enhancer conferred slow-muscle-preferential activity upon minimal thymidine kinase Transgenic confirmed role restricting expression Hence, may be used rapidly define elements direct myofiber-type-specific prior generation transgenic mice.