Dr. Dorris et K. Struhl, Artificial recruitment of TFIID, but not RNA polymerase II holoenzyme, activates transcription in mammalian cells, MOL CELL B, 20(12), 2000, pp. 4350-4358
In yeast cells, transcriptional activation occurs when the RNA polymerase I
I (Pol II) machinery is artificially recruited to a promoter by fusing indi
vidual components of this machinery to a DNA-binding domain. Here, we show
that artificial recruitment of components of the TFIID complex can activate
transcription in mammalian cells. Surprisingly, artificial recruitment of
TATA-binding protein (TBP) activates transiently transfected and chromosoma
lly integrated promoters with equal efficiency, whereas artificial recruitm
ent of TBP-associated factors activates only chromosomal reporters. In cont
rast, artificial recruitment of various components of the mammalian Pol II
holoenzyme does not confer transcriptional activation, nor does it result i
n synergistic activation in combination with natural activation domains. In
the one case examined in more detail, the Srb7 fusion failed to activate d
espite being associated with the Pol II holoenzyme and being directly recru
ited to the promoter. Interestingly, some acidic activation domains are les
s effective when the promoter is chromosomally integrated rather than trans
iently transfected, whereas the Spl glutamine-rich activation domain is mor
e effective on integrated reporters. Thus, yeast and mammalian cells differ
with respect to transcriptional activation by artificial recruitment of th
e Pol II holoenzyme.