Volume 270,
Number 43,
Issue of October 27, 1995 pp. 25785-25791
©1995 by The American Society for Biochemistry and Molecular Biology, Inc.
Two
Homologous Enhancer Elements in the Chicken Vimentin Gene May Bind a
Nuclear Factor in Common with a Nearby Silencer Element
(Received for publication, May 30, 1995)
Edward B.
Perkins,
Janet
G.
Cunningham ,
Alma M.
Bracete ,
Zendra E.
Zehner
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.