scholarly journals Transcription initiated by RNA polymerase II and purified transcription factors from liver. Transcription factors alpha, beta gamma, and delta promote formation of intermediates in assembly of the functional preinitiation complex.

1990 ◽  
Vol 265 (13) ◽  
pp. 7559-7563 ◽  
Author(s):  
R C Conaway ◽  
J W Conaway
1998 ◽  
Vol 18 (5) ◽  
pp. 2876-2883 ◽  
Author(s):  
Song He ◽  
Steven Jay Weintraub

ABSTRACT Recently, it was found that if either the TATA binding protein or RNA polymerase II holoenzyme is artificially tethered to a promoter, transcription is activated. This finding provided presumptive evidence that upstream activating proteins function by recruiting components of the preinitiation complex (PIC) to the promoter. To date, however, there have been no studies demonstrating that upstream factors actually recruit components of the PIC to the promoter in vivo. Therefore, we have studied the mechanism of action of two disparate transactivating domains. We present a series of in vivo functional assays that demonstrate that each of these proteins targets different components of the PIC for recruitment. We show that, by targeting different components of the PIC for recruitment, these activating domains can cooperate with each other to activate transcription synergistically and that, even within one protein, two different activating subdomains can activate transcription synergistically by cooperating to recruit different components of the PIC. Finally, considering our work together with previous studies, we propose that certain transcription factors both recruit components of the PIC and facilitate steps in transcriptional activation that occur subsequent to recruitment.


1997 ◽  
Vol 110 (15) ◽  
pp. 1781-1791 ◽  
Author(s):  
M.A. Grande ◽  
I. van der Kraan ◽  
L. de Jong ◽  
R. van Driel

We have investigated the spatial relationship between sites containing newly synthesized RNA and domains containing proteins involved in transcription, such as RNA polymerase II and the transcription factors TFIIH, Oct1, BRG1, E2F-1 and glucocorticoid receptors, using dual immunofluorescence labelling followed by confocal microscopy on cultured cells. As expected, a high degree of colocalisation between the RNA polymerase II and sites containing newly synthesised RNA was observed. Like the newly synthesised RNA and the RNA polymerase II, we found that all the transcription factors that we studied are distributed more or less homogeneously throughout the nucleoplasm, occupying numerous small domains. In addition to these small domains, TFIIH was found concentrated in coiled bodies and Oct1 in a single large domain of about 1.5 microm in 30% of the cells in an asynchronous HeLa cell culture. Remarkably, we found little or no relationship between the spatial distribution of the glucocorticoid receptor, Oct1 and E2F-1 on the one hand and RNA polymerase II and transcription sites on the other hand. In contrast, a significant but incomplete overlap was observed between the spatial distributions of transcription sites and BRG1 and TFIIH. These results indicate that many of the transcription factor-rich nuclear domains are not actively involved in transcription. They may represent incomplete transcription initiation complexes, inhibitory complexes, or storage sites.


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