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The FACT (facilitates chromatin transcription) complex is required for transcript elongation through nucleosomes by RNA polymerase II (Pol II) in vitro. Here, we show that FACT facilitates Pol II-driven transcription by destabilizing nucleosomal structure so that one histone H2A-H2B dimer is removed during enzyme passage. We also demonstrate that FACT(More)
Nucleosomes, the nucleohistone subunits of chromatin, are present on transcribed eukaryotic genes but do not prevent transcription. It is shown here that the large yeast RNA polymerase III transcribes through a single nucleosome. This takes place through a direct internal nucleosome transfer in which histones never leave the DNA template. During this(More)
RNA polymerase II (Pol II) must transcribe genes in a chromatin environment in vivo. We examined transcription by Pol II through nucleosome cores in vitro. At physiological and lower ionic strengths, a mononucleosome imposes a strong block to elongation, which is relieved at increased ionic strength. Passage of Pol II causes a quantitative loss of one(More)
The mechanism by which nucleosome cores are displaced and re-formed during transcription in vitro has been investigated. A nucleosome core was assembled on a short linear DNA template (227 bp) containing an SP6 RNA polymerase promoter and a nucleosome-positioning sequence. Transcription induced the translocation of the nucleosome core over 75 or 80 bp to(More)
In eukaryotic genomes, nucleosomes function to compact DNA and to regulate access to it both by simple physical occlusion and by providing the substrate for numerous covalent epigenetic tags. While competition with other DNA-binding factors and action of chromatin remodeling enzymes significantly affect nucleosome formation in vivo, nucleosome positions in(More)
We have studied the kinetics of transcription through a nucleosome core. RNA polymerase transcribes the first approximately 25 bp of nucleosomal DNA rapidly, but then hits a barrier and continues slowly to the nucleosomal dyad region. Here, the barrier disappears and the transcript is completed at a rapid rate, as if on free DNA, indicating that histone(More)
The nitrogen-regulated genes and operons of the Ntr regulon of Escherichia coli are activated by the enhancer-binding transcriptional activator NRI approximately P (NtrC approximately P). Here, we examined the activation of the glnA, glnK, and nac promoters as cells undergo the transition from growth on ammonia to nitrogen starvation and examined the(More)
In the cell, RNA polymerase II (pol II) efficiently transcribes DNA packaged into nucleosomes, but in vitro encounters with the nucleosomes induce catalytic inactivation (arrest) of the pol II core enzyme. To determine potential mechanisms making nucleosomes transparent to transcription in vivo, we analyzed the nature of the nucleosome-induced arrest. We(More)
Remodeling machines play an essential role in the control of gene expression, but how their activity is regulated is not known. Here we report that the nuclear protein nucleolin possesses a histone chaperone activity and that this factor greatly enhances the activity of the chromatin remodeling machineries SWI/SNF and ACF. Interestingly, nucleolin is able(More)
Enhancers are regulatory DNA elements that can activate their genomic targets over a large distance. The mechanism of enhancer action over large distance is unknown. Activation of the glnAp2 promoter by NtrC-dependent enhancer in Escherichia coli was analyzed by using a purified system supporting multiple-round transcription in vitro. The data suggest that(More)