XB-IMG-131958
Xenbase Image ID: 131958
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Fig. 3. Transcription activation by Xbra and Ntl and repression of activation by a
dominant interfering Xbra-EnR construct. NIH3T3 cells were lipofected with the
indicated effector plasmids together with a chloramphenicol acetyl transferase (CAT)
reporter plasmid carrying two copies of the Brachyury-binding site (Kispert and
Herrmann, 1993) upstream of a minimal promoter. Plasmids encoding wild-type Xbra
(lane 2) or wild-type Ntl (lane 4) cause activation of transcription while the Xbra and
Ntl alleles lacking the putative activator domain (see Fig. 2) have little or no effect
(lanes 3 and 5). A plasmid encoding an Xbra allele in which the activation domain is
replaced by the Drosophila engrailed repressor domain (Xbra-EnR) causes no
activation (lanes 6 and 8) and it inhibits activation due to Xbra in a dose-dependent
manner, with complete inhibition obtained with a two-fold excess of Xbra-EnR over
Xbra (lanes 7 and 9). This experiment was carried out three times, with similar results
obtained each time. Loading was normalised by reference to levels of b-galactosidase
activity derived from the co-transfected MLVlacZ plasmid. Mean levels of stimulation
are indicated. Xbra did not cause transcription activation in the absence of a
Brachyury-binding site (not shown). Image published in: Conlon FL et al. (1996) Copyright © 1996. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View |