Down-regulation of vimentin gene expression during myogenesis is controlled by a 5′-flanking sequence

Abstract

During myogenesis, the intermediate filament proteins vimentin and desmin are differentially expressed. While desmin levels increase dramatically, vimentin mRNA levels decrease substantially. Here, we show that transfected whole- and mini-vimentin-coding genes ( Vim) are expressed in fibroblasts (mouse L cells) and down-regulated during muscle cell differentiation in culture. Functional assays with 5 ' -end Vim ::cat constructs demonstrate that this repression is controlled by a 5′-element (nt −321 to −160). This region is distinct from Vim promoter elements (nt −160 to + 71) which do not contribute to vimentin's down-regulation during myogenesis.