scholarly journals Protein-DNA cross-linking reveals dramatic variation in RNA polymerase II density on different histone repeats of Drosophila melanogaster.

1987 ◽  
Vol 7 (9) ◽  
pp. 3341-3344 ◽  
Author(s):  
D S Gilmour ◽  
J T Lis

In Drosophila melanogaster the five histone genes are within a 5-kilobase region which is repeated 100 times at a single chromosomal site. These 5-kilobase repeats are of two distinct classes, short and long, that differ by approximately 200 base pairs of DNA in the spacer region between the H1 and H3 genes. Since the mRNA-homologous regions of the repeats are highly conserved, one cannot examine differential expression of the repeats by classical hybridization methods. In this study, we assessed their transcriptional activity by measuring in vivo the relative amounts of RNA polymerase II that were cross-linked by UV irradiation to the two different histone repeats. The RNA polymerase II density on the long repeat in Schneider line 2 cells was strikingly lower (10-fold) than the density on the short repeat. The magnitude of this difference cannot be accounted for by reduced transcription of only one or two genes of the repeat. The density of topoisomerase I, an indicator of transcriptional activity, was also much higher on the short repeat than on the long repeat of line 2 cells. In contrast, the RNA polymerase II density was slightly higher on the long repeat than on the short repeat in a second cell line, KcH. The major difference between active (KcH) and inactive (S2) long repeats resides in the H1-H3 nontranscribed spacer. This portion of the spacer may contain a component necessary for expression that can act over a moderate distance and affect multiple genes of the repeat.

1987 ◽  
Vol 7 (9) ◽  
pp. 3341-3344
Author(s):  
D S Gilmour ◽  
J T Lis

In Drosophila melanogaster the five histone genes are within a 5-kilobase region which is repeated 100 times at a single chromosomal site. These 5-kilobase repeats are of two distinct classes, short and long, that differ by approximately 200 base pairs of DNA in the spacer region between the H1 and H3 genes. Since the mRNA-homologous regions of the repeats are highly conserved, one cannot examine differential expression of the repeats by classical hybridization methods. In this study, we assessed their transcriptional activity by measuring in vivo the relative amounts of RNA polymerase II that were cross-linked by UV irradiation to the two different histone repeats. The RNA polymerase II density on the long repeat in Schneider line 2 cells was strikingly lower (10-fold) than the density on the short repeat. The magnitude of this difference cannot be accounted for by reduced transcription of only one or two genes of the repeat. The density of topoisomerase I, an indicator of transcriptional activity, was also much higher on the short repeat than on the long repeat of line 2 cells. In contrast, the RNA polymerase II density was slightly higher on the long repeat than on the short repeat in a second cell line, KcH. The major difference between active (KcH) and inactive (S2) long repeats resides in the H1-H3 nontranscribed spacer. This portion of the spacer may contain a component necessary for expression that can act over a moderate distance and affect multiple genes of the repeat.


1985 ◽  
Vol 5 (8) ◽  
pp. 2009-2018
Author(s):  
D S Gilmour ◽  
J T Lis

We describe a method for examining the in vivo distribution of a protein on specific eucaryotic DNA sequences. In this method, proteins are cross-linked to DNA in intact cells, and the protein-DNA adducts are isolated by immunoprecipitation with antiserum against the protein. Characterization of the DNA cross-linked to the precipitated protein identifies the sequences with which the protein is associated in vivo. Here, we applied these methods to detect RNA polymerase II-DNA interactions in heat-shocked and untreated Drosophila melanogaster Schneider line 2 cells. The level of RNA polymerase II associated with several heat shock genes increased dramatically in response to heat shock, whereas the level associated with the copia genes decreased, indicating that both induction of heat shock gene expression and repression of the copia gene expression by heat shock occur at the transcriptional level. Low levels of RNA polymerase II were present on DNA outside of the transcription units, and for at least two genes, hsp83 and hsp26, RNA polymerase II initiated binding near the transcription start site. Moreover, for hsp70, the density of RNA polymerase II on sequences downstream of the polyadenylate addition site was much lower than that observed on the gene internal sequences. Examination of the amount of specific restriction fragments cross-linked to RNA polymerase II provides a means of detecting RNA polymerase II on individual members of multigene families. This analysis shows that RNA polymerase II is associated with only one of the two cytoplasmic actin genes.


1986 ◽  
Vol 6 (11) ◽  
pp. 3984-3989 ◽  
Author(s):  
D S Gilmour ◽  
J T Lis

By using a protein-DNA cross-linking method (D. S. Gilmour and J. T. Lis, Mol. Cell. Biol. 5:2009-2018, 1985), we examined the in vivo distribution of RNA polymerase II on the hsp70 heat shock gene in Drosophila melanogaster Schneider line 2 cells. In heat shock-induced cells, a high level of RNA polymerase II was detected on the entire gene, while in noninduced cells, the RNA polymerase II was confined to the 5' end of the hsp70 gene, predominantly between nucleotides -12 and +65 relative to the start of transcription. This association of RNA polymerase II was apparent whether the cross-linking was performed by a 10-min UV irradiation of chilled cells with mercury vapor lamps or by a 40-microsecond irradiation of cells with a high-energy xenon flash lamp. We hypothesize that RNA polymerase II has access to, and a high affinity for, the promoter region of this gene before induction, and this poised RNA polymerase II may be critical in the mechanism of transcription activation.


1988 ◽  
Vol 8 (5) ◽  
pp. 2021-2033 ◽  
Author(s):  
D E Ayer ◽  
W S Dynan

Unlike most genes transcribed by RNA polymerase II, the simian virus 40 late transcription unit does not have a TATA box. To determine what sequences are required for initiation at the major late mRNA cap site of simian virus 40, clustered point mutations were constructed and tested for transcriptional activity in vitro and in vivo. Three promoter elements were defined. The first is centered 31 base pairs upstream of the cap site in a position normally reserved for a TATA box. The second is at the cap site. The third occupies a novel position centered 28 base pairs downstream of the cap site within a protein-coding sequence. The ability of RNA polymerase II to recognize this promoter suggests that there is greater variation in promoter architecture than had been believed previously.


2001 ◽  
Vol 21 (23) ◽  
pp. 7956-7970 ◽  
Author(s):  
Rosemary E. Kiernan ◽  
Stéphane Emiliani ◽  
Keiko Nakayama ◽  
Anna Castro ◽  
Jean Claude Labbé ◽  
...  

ABSTRACT CDK9 paired with cyclin T1 forms the human P-TEFb complex and stimulates productive transcription through phosphorylation of the RNA polymerase II C-terminal domain. Here we report that CDK9 is ubiquitinated and degraded by the proteasome whereas cyclin T1 is stable. SCFSKP2 was recruited to CDK9/cyclin T1 via cyclin T1 in an interaction requiring its PEST domain. CDK9 ubiquitination was modulated by cyclin T1 and p45SKP2. CDK9 accumulated in p45SKP2−/− cells, and its expression during the cell cycle was periodic. The transcriptional activity of CDK9/cyclin T1 on the class II major histocompatibility complex promoter could be regulated by CDK9 degradation in vivo. We propose a novel mechanism whereby recruitment of SCFSKP2 is mediated by cyclin T1 while ubiquitination occurs exclusively on CDK9.


1988 ◽  
Vol 8 (5) ◽  
pp. 2021-2033
Author(s):  
D E Ayer ◽  
W S Dynan

Unlike most genes transcribed by RNA polymerase II, the simian virus 40 late transcription unit does not have a TATA box. To determine what sequences are required for initiation at the major late mRNA cap site of simian virus 40, clustered point mutations were constructed and tested for transcriptional activity in vitro and in vivo. Three promoter elements were defined. The first is centered 31 base pairs upstream of the cap site in a position normally reserved for a TATA box. The second is at the cap site. The third occupies a novel position centered 28 base pairs downstream of the cap site within a protein-coding sequence. The ability of RNA polymerase II to recognize this promoter suggests that there is greater variation in promoter architecture than had been believed previously.


1986 ◽  
Vol 6 (11) ◽  
pp. 3984-3989
Author(s):  
D S Gilmour ◽  
J T Lis

By using a protein-DNA cross-linking method (D. S. Gilmour and J. T. Lis, Mol. Cell. Biol. 5:2009-2018, 1985), we examined the in vivo distribution of RNA polymerase II on the hsp70 heat shock gene in Drosophila melanogaster Schneider line 2 cells. In heat shock-induced cells, a high level of RNA polymerase II was detected on the entire gene, while in noninduced cells, the RNA polymerase II was confined to the 5' end of the hsp70 gene, predominantly between nucleotides -12 and +65 relative to the start of transcription. This association of RNA polymerase II was apparent whether the cross-linking was performed by a 10-min UV irradiation of chilled cells with mercury vapor lamps or by a 40-microsecond irradiation of cells with a high-energy xenon flash lamp. We hypothesize that RNA polymerase II has access to, and a high affinity for, the promoter region of this gene before induction, and this poised RNA polymerase II may be critical in the mechanism of transcription activation.


1985 ◽  
Vol 5 (8) ◽  
pp. 2009-2018 ◽  
Author(s):  
D S Gilmour ◽  
J T Lis

We describe a method for examining the in vivo distribution of a protein on specific eucaryotic DNA sequences. In this method, proteins are cross-linked to DNA in intact cells, and the protein-DNA adducts are isolated by immunoprecipitation with antiserum against the protein. Characterization of the DNA cross-linked to the precipitated protein identifies the sequences with which the protein is associated in vivo. Here, we applied these methods to detect RNA polymerase II-DNA interactions in heat-shocked and untreated Drosophila melanogaster Schneider line 2 cells. The level of RNA polymerase II associated with several heat shock genes increased dramatically in response to heat shock, whereas the level associated with the copia genes decreased, indicating that both induction of heat shock gene expression and repression of the copia gene expression by heat shock occur at the transcriptional level. Low levels of RNA polymerase II were present on DNA outside of the transcription units, and for at least two genes, hsp83 and hsp26, RNA polymerase II initiated binding near the transcription start site. Moreover, for hsp70, the density of RNA polymerase II on sequences downstream of the polyadenylate addition site was much lower than that observed on the gene internal sequences. Examination of the amount of specific restriction fragments cross-linked to RNA polymerase II provides a means of detecting RNA polymerase II on individual members of multigene families. This analysis shows that RNA polymerase II is associated with only one of the two cytoplasmic actin genes.


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