Two homologous enhancer elements in the chicken vimentin gene may bind a nuclear factor in common with a nearby silencer element.
Vimentin, a cytoskeletal protein belonging to the intermediate filament protein family, exhibits a complex pattern of expression. In the case of the chicken vimentin gene, several regulatory elements within the 5' region of the gene have been characterized, including an enhancer activity between -160 and -320, which may contribute to the down-regulation of vimentin expression during myogenesis. In this study, sequences within this region were examined via transient transfections of various deletion constructs, and two distinct enhancer elements were found, one on either side of a previously described silencer element. These two enhancer elements also enhanced transcription when fused separately to the basal promoter region of the chicken vimentin gene. Gel mobility shift assays, UV cross-linking experiments, and DNase I protection studies indicate that these two enhancer elements and the silencer element all contain a common binding site for the previously described 95-kDa silencer element binding protein, suggesting that this regulatory protein can act as both an activator and a repressor.
Perkins
E B
EB
Department of Biochemistry and Molecular Biophysics, Medical College of Virginia/Virginia Commonwealth University, Richmond 23298, USA.
Cunningham
J G
JG
Bracete
A M
AM
Zehner
Z E
ZE
D000818:Animals; D001483:Base Sequence; D002645:Chickens; D002846:Chromatography, Affinity; D018983:DNA Footprinting; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D006367:HeLa Cells; D006801:Humans; D007739:L Cells; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D017384:Sequence Deletion; D014466:Ultraviolet Rays; D014746:Vimentin / Q000235:genetics*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D014746:Vimentin