scholarly journals Sequence elements essential for function of the Xenopus laevis ribosomal DNA enhancers.

1988 ◽  
Vol 8 (10) ◽  
pp. 4282-4288 ◽  
Author(s):  
C S Pikaard ◽  
R H Reeder
Keyword(s):  
Xenopus Laevis ◽  
Ribosomal Dna ◽  
Base Pair ◽  
Intergenic Spacer ◽  
Current Evidence ◽  
Enhancer Element ◽  
Intergenic Spacer Region ◽  
Sequence Elements ◽  
Polymerase I ◽  
In Cis

The intergenic spacer region of the Xenopus laevis ribosomal DNA contains multiple elements which are either 60 or 81 base pairs long. Clusters of these elements have previously been shown to act as position- and distance-independent enhancers on an RNA polymerase I promoter when located in cis. By a combination of deletion and linker scanner mutagenesis we show that the sequences essential for enhancer function are located within a 56-base-pair region that is present in both the 60- and 81-base-pair repeats. Within the 56-base-pair region one linker scanner mutation was found to be relatively neutral, suggesting that each enhancer element may be composed of two smaller domains. Each 56-base-pair region appears to be an independent enhancer with multiple enhancers being additive in effect. We review the current evidence concerning the mechanism of action of these enhancers.

Sequence elements essential for function of the Xenopus laevis ribosomal DNA enhancers

1988 ◽  
Vol 8 (10) ◽  
pp. 4282-4288
Author(s):  
C S Pikaard ◽  
R H Reeder
Keyword(s):  
Xenopus Laevis ◽  
Ribosomal Dna ◽  
Base Pair ◽  
Intergenic Spacer ◽  
Current Evidence ◽  
Enhancer Element ◽  
Intergenic Spacer Region ◽  
Sequence Elements ◽  
Polymerase I ◽  
In Cis

The intergenic spacer region of the Xenopus laevis ribosomal DNA contains multiple elements which are either 60 or 81 base pairs long. Clusters of these elements have previously been shown to act as position- and distance-independent enhancers on an RNA polymerase I promoter when located in cis. By a combination of deletion and linker scanner mutagenesis we show that the sequences essential for enhancer function are located within a 56-base-pair region that is present in both the 60- and 81-base-pair repeats. Within the 56-base-pair region one linker scanner mutation was found to be relatively neutral, suggesting that each enhancer element may be composed of two smaller domains. Each 56-base-pair region appears to be an independent enhancer with multiple enhancers being additive in effect. We review the current evidence concerning the mechanism of action of these enhancers.

scholarly journals The Xenopus ribosomal DNA 60- and 81-base-pair repeats are position-dependent enhancers that function at the establishment of the preinitiation complex: analysis in vivo and in an enhancer-responsive in vitro system.

1989 ◽  
Vol 9 (11) ◽  
pp. 5093-5104 ◽  
Author(s):  
L K Pape ◽  
J J Windle ◽  
E B Mougey ◽  
B Sollner-Webb
Keyword(s):  
Ribosomal Dna ◽  
Base Pair ◽  
Complex Analysis ◽  
Initiation Site ◽  
In Vitro System ◽  
Sequential Addition ◽  
Polymerase I ◽  
In Cis

Although it is generally believed that the 60- and 81-base-pair (60/81-bp) repeats of the Xenopus laevis ribosomal DNA (rDNA) spacer are position-independent transcriptional enhancers, this has not been shown directly. We have now developed a critical assay which proves that the 60/81-bp repeats do, in fact, stimulate transcription from promoters in cis and that they function in both orientations and when up to 1 kilobase pair from the initiation site. However, contrary to the widely accepted view, these elements are found to be highly position dependent, for they have no net effect when downstream of the initiation site within the transcribed region and they behave as transcriptional silencers of promoters in cis when moved greater than 2 kilobase pairs upstream of the initiation site. The 60/81-bp elements therefore are position-dependent 5' enhancers. We also found that this rDNA enhancer was polymerase I specific and that it was composed of duplicated, individually functional elements. Finally, we report an in vitro system that reproduces both cis enhancement and trans competition by the 60/81-bp repeats. Sequential-addition studies in this system demonstrated that the rDNA enhancer functions in trans at or before establishment of the stable transcription complex, not subsequently at each round of transcription.

The Xenopus ribosomal DNA 60- and 81-base-pair repeats are position-dependent enhancers that function at the establishment of the preinitiation complex: analysis in vivo and in an enhancer-responsive in vitro system

1989 ◽  
Vol 9 (11) ◽  
pp. 5093-5104
Author(s):  
L K Pape ◽  
J J Windle ◽  
E B Mougey ◽  
B Sollner-Webb
Keyword(s):  
Ribosomal Dna ◽  
Base Pair ◽  
Complex Analysis ◽  
Initiation Site ◽  
In Vitro System ◽  
Sequential Addition ◽  
Polymerase I ◽  
In Cis

Although it is generally believed that the 60- and 81-base-pair (60/81-bp) repeats of the Xenopus laevis ribosomal DNA (rDNA) spacer are position-independent transcriptional enhancers, this has not been shown directly. We have now developed a critical assay which proves that the 60/81-bp repeats do, in fact, stimulate transcription from promoters in cis and that they function in both orientations and when up to 1 kilobase pair from the initiation site. However, contrary to the widely accepted view, these elements are found to be highly position dependent, for they have no net effect when downstream of the initiation site within the transcribed region and they behave as transcriptional silencers of promoters in cis when moved greater than 2 kilobase pairs upstream of the initiation site. The 60/81-bp elements therefore are position-dependent 5' enhancers. We also found that this rDNA enhancer was polymerase I specific and that it was composed of duplicated, individually functional elements. Finally, we report an in vitro system that reproduces both cis enhancement and trans competition by the 60/81-bp repeats. Sequential-addition studies in this system demonstrated that the rDNA enhancer functions in trans at or before establishment of the stable transcription complex, not subsequently at each round of transcription.

scholarly journals PCR amplification and polymorphism analysis of the intergenic spacer region of ribosomal DNA in Tuber borchii

2002 ◽  
Vol 157 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Pasquapina Ciarmela ◽  
Lucia Potenza ◽  
Luigi Cucchiarini ◽  
Sabrina Zeppa ◽  
Vilberto Stocchi
Keyword(s):  
Ribosomal Dna ◽  
Pcr Amplification ◽  
Intergenic Spacer ◽  
Polymorphism Analysis ◽  
Tuber Borchii ◽  
Intergenic Spacer Region

scholarly journals Bartonella vinsonii subsp.berkhoffii as an Agent of Afebrile Blood Culture-Negative Endocarditis in a Human

2000 ◽  
Vol 38 (4) ◽  
pp. 1698-1700 ◽  
Author(s):  
Véronique Roux ◽  
Susannah J. Eykyn ◽  
Sarah Wyllie ◽  
Didier Raoult
Keyword(s):  
Blood Culture ◽  
Ribosomal Dna ◽  
Citrate Synthase ◽  
Pcr Amplification ◽  
Intergenic Spacer ◽  
Bacterial Identification ◽  
Gene Encoding ◽  
Intergenic Spacer Region ◽  
16S Ribosomal Dna ◽  
Culture Negative

We report a case of endocarditis in a human infected withBartonella vinsonii subsp. berkhoffii, which causes bacteremia and endocarditis in dogs. Bacterial identification was established by PCR amplification and sequencing of an intergenic spacer region (ITS1), 16S ribosomal DNA, and a gene encoding citrate synthase (gltA). Bartonella antibodies were detected by immunofluorescence.

Simple species identification of Trichinella isolates by amplification and sequencing of the 5S ribosomal DNA intergenic spacer region

2005 ◽  
Vol 132 (1-2) ◽  
pp. 57-61 ◽  
Author(s):  
Aymeric De Bruyne ◽  
Hélène Yera ◽  
Franck Le Guerhier ◽  
Pascal Boireau ◽  
Jean Dupouy-Camet
Keyword(s):  
Species Identification ◽  
Ribosomal Dna ◽  
Intergenic Spacer ◽  
Intergenic Spacer Region
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