scholarly journals Telomeric location of Giardia rDNA genes.

1991 ◽  
Vol 11 (6) ◽  
pp. 3326-3330 ◽  
Author(s):  
R D Adam ◽  
T E Nash ◽  
T E Wellems
Keyword(s):  
Tandem Repeats ◽  
Dna Analysis ◽  
Large Subunit ◽  
Intergenic Spacer ◽  
Rdna Sequence ◽  
Rrna Genes ◽  
Rdna Genes ◽  
Pulsed Field ◽  
Large Subunit Rdna ◽  
A Site

Giardia lamblia telomeres have been isolated from a library enriched for repaired chromosome ends by (i) screening with a Plasmodium falciparum telomere and (ii) differential hybridization with Bal 31-digested and total G. lamblia DNA. Analysis of three clones isolated by this strategy has identified multiple tandem repeats of the 5-mer TAGGG. An oligonucleotide containing these repeats recognizes Bal 31-sensitive bands in Southern hybridizations and detects all G. lamblia chromosomes in pulsed-field gel electrophoresis separations. An abrupt transition from the G. lamblia rDNA sequence to telomeric repeats has been found in all three clones. In two of the clones the transition occurs at the same site, near the beginning of the large subunit rDNA sequence. In the third clone the transition occurs at a site in the intergenic spacer sequence between the rDNA genes. Hybridization of an rDNA probe to a pulsed-field separation of G. lamblia chromosomes indicates that rDNA genes are present on several chromosomes but vary in location from isolate to isolate. These results suggest that rRNA genes are clustered at telomeric locations in G. lamblia and that these clusters are mobile.

Telomeric location of Giardia rDNA genes

1991 ◽  
Vol 11 (6) ◽  
pp. 3326-3330
Author(s):  
R D Adam ◽  
T E Nash ◽  
T E Wellems
Keyword(s):  
Tandem Repeats ◽  
Dna Analysis ◽  
Large Subunit ◽  
Intergenic Spacer ◽  
Rdna Sequence ◽  
Rrna Genes ◽  
Rdna Genes ◽  
Pulsed Field ◽  
Large Subunit Rdna ◽  
A Site

Giardia lamblia telomeres have been isolated from a library enriched for repaired chromosome ends by (i) screening with a Plasmodium falciparum telomere and (ii) differential hybridization with Bal 31-digested and total G. lamblia DNA. Analysis of three clones isolated by this strategy has identified multiple tandem repeats of the 5-mer TAGGG. An oligonucleotide containing these repeats recognizes Bal 31-sensitive bands in Southern hybridizations and detects all G. lamblia chromosomes in pulsed-field gel electrophoresis separations. An abrupt transition from the G. lamblia rDNA sequence to telomeric repeats has been found in all three clones. In two of the clones the transition occurs at the same site, near the beginning of the large subunit rDNA sequence. In the third clone the transition occurs at a site in the intergenic spacer sequence between the rDNA genes. Hybridization of an rDNA probe to a pulsed-field separation of G. lamblia chromosomes indicates that rDNA genes are present on several chromosomes but vary in location from isolate to isolate. These results suggest that rRNA genes are clustered at telomeric locations in G. lamblia and that these clusters are mobile.

scholarly journals Non-Coding, RNAPII-Dependent Transcription at the Promoters of rRNA Genes Regulates Their Chromatin State in S. cerevisiae

2021 ◽  
Vol 7 (3) ◽  
pp. 41
Author(s):  
Emma Lesage ◽  
Jorge Perez-Fernandez ◽  
Sophie Queille ◽  
Christophe Dez ◽  
Olivier Gadal ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Tandem Repeats ◽  
Chromatin State ◽  
Rrna Genes ◽  
Rdna Genes ◽  
Regulatory Pathways ◽  
Chromatin States ◽  
Non Coding Rnas ◽  
Pervasive Transcription

Pervasive transcription is widespread in eukaryotes, generating large families of non-coding RNAs. Such pervasive transcription is a key player in the regulatory pathways controlling chromatin state and gene expression. Here, we describe long non-coding RNAs generated from the ribosomal RNA gene promoter called UPStream-initiating transcripts (UPS). In yeast, rDNA genes are organized in tandem repeats in at least two different chromatin states, either transcribed and largely depleted of nucleosomes (open) or assembled in regular arrays of nucleosomes (closed). The production of UPS transcripts by RNA Polymerase II from endogenous rDNA genes was initially documented in mutants defective for rRNA production by RNA polymerase I. We show here that UPS are produced in wild-type cells from closed rDNA genes but are hidden within the enormous production of rRNA. UPS levels are increased when rDNA chromatin states are modified at high temperatures or entering/leaving quiescence. We discuss their role in the regulation of rDNA chromatin states and rRNA production.

Genomic fingerprinting ofFrankiamicrosymbionts fromCeanothuscopopulations using repetitive sequences and polymerase chain reactions

1999 ◽  
Vol 77 (9) ◽  
pp. 1220-1230 ◽  
Author(s):  
Soon-Chun Jeong ◽  
David D Myrold
Keyword(s):  
Dna Sequencing ◽  
Dna Analysis ◽  
Repetitive Sequences ◽  
Intergenic Spacer ◽  
Rrna Genes ◽  
23S Rrna ◽  
Genomic Fingerprinting ◽  
Chain Reactions ◽  
Intergenic Spacer Region ◽  
Polymerase Chain

Specificity between Ceanothus species and their microsymbionts, Frankia, were investigated with nodules collected from three geographically separated copopulations of Ceanothus species. Nodules were analyzed using DNA sequencing and repetitive sequence polymerase chain reaction (rep-PCR) techniques. DNA sequencing of the intergenic spacer region between 16S and 23S rRNA genes suggested that Ceanothus-microsymbiotic Frankia are closely related at the intraspecific level. Diversity of the microsymbionts was further analyzed by genomic fingerprinting using repetitive sequences and PCR. A newly designed direct repeat (DR) sequence and a BOX sequence were used as PCR primers after justification that these primers can generate Frankia-specific fingerprints from nodule DNA. Analysis of the nodules using BOX- and DR-PCR showed that Ceanothus-microsymbiotic Frankia exhibited less diversity within each copopulation than among copopulations. These data suggested that geographic separation plays a more important role for divergence of Ceanothus-microsymbiotic Frankia than host plant.Key words: Frankia, Ceanothus, rep-PCR, diversity.

Analysis of the ITS region and partial ssu and lsu rRNA genes ofBlastocystisandProteromonas lacertae

Parasitology ◽  
2005 ◽  
Vol 131 (2) ◽  
pp. 187-196 ◽  
Author(s):  
J. D. HOEVERS ◽  
K. F. SNOWDEN
Keyword(s):  
Large Subunit ◽  
Geographic Origin ◽  
Its Region ◽  
Small Subunit ◽  
Rdna Sequence ◽  
Rrna Genes ◽  
Small Subunit Rrna ◽  
Chattonella Marina ◽  
Internal Transcribed Spacer Region ◽  
Cylindrotheca Closterium

Blastocystisis a common single-celled enteric parasite found in a large variety of hosts. Recent molecular analysis supports the concept that this eukaryotic organism is a stramenopile most closely related toProteromonas lacertae, a parasite of reptiles. In this study, the internal transcribed spacer region, partial small subunit rRNA and large subunit rRNA genes from 7Blastocystisisolates (5 human, 1 pig and 1 sheep), and aProteromonas lacertaeisolate were amplified by PCR, cloned and sequenced.Blastocystiswas found to be a typical eukaryote with both ITS1 and ITS2 regions present. Phylogenetic analysis based on the entire PCR amplicon revealed that theBlastocystisisolates did not segregate according to host or geographic origin. The highest sequence identities with the conservedBlastocystis5·8S rDNA sequence were with the stramenopilesFibrocapsa japonica,Chattonella marina,Cylindrotheca closteriumandHyphochytrium catenoides. The most parsimonious tree based on the 5·8S rDNA sequence fromP. lacertae, 11 other stramenopiles, 2 fungi, 3 algae and 3 alveolates showedBlastocystispositioned within the stramenopiles, withP. lacertaeas its closest relative. This work therefore supports the hypothesis thatBlastocystisis most closely related toP. lacertae, and that it should be regarded as an unusual stramenopile.

scholarly journals The Large Subunit rDNA Sequence of Plasmodiophora brassicae Does not Contain Intra-species Polymorphism

Protist ◽  
2016 ◽  
Vol 167 (6) ◽  
pp. 544-554 ◽  
Author(s):  
Arne Schwelm ◽  
Cédric Berney ◽  
Christina Dixelius ◽  
David Bass ◽  
Sigrid Neuhauser
Keyword(s):  
Plasmodiophora Brassicae ◽  
Large Subunit ◽  
Rdna Sequence ◽  
Large Subunit Rdna

Organization of the 5S rRNA genes in the soybean Glycine max (L.) Merrill and conservation of the 5S rDNA repeat structure in higher plants

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 486-494 ◽  
Author(s):  
S. G. Gottlob-McHugh ◽  
M. Lévesque ◽  
K. MacKenzie ◽  
M. Olson ◽  
O. Yarosh ◽  
...  
Keyword(s):  
Glycine Max ◽  
Tandem Repeats ◽  
Higher Plants ◽  
5S Rdna ◽  
Rdna Sequence ◽  
5S Rrna ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Glycine Max L ◽  
5S Rdna Sequence

The 5S rRNA gene of the soybean Glycine max (L.) Merr. has been cloned on a 556-bp fragment of DNA and sequenced. This fragment contains two copies of the soybean 5S rDNA sequence, one intact and one truncated, separated by noncoding DNA. We have used this clone to investigate the organization of the 5S genes within the soybean genome and the extent of their methylation. Our results demonstrate that soybean 5S genes are clustered, organized into tandem repeats of 330 bp, and extensively methylated. Hybridization of the 5S sequence to Southern transfers of soybean DNA digested with BamHI reveals a striking ladderlike pattern. Hybridization of the soybean 5S sequence to a wide variety of plant DNAs results in similar patterns, suggesting that the 5S rDNA sequence, gene organization, and methylation pattern are conserved in many higher plants.Key words: 5S rDNA, sequence, methylation, soybean, repeat conservation.

Theileria parva ribosomal internal transcribed spacer sequences exhibit extensive polymorphism and mosaic evolution: application to the characterization of parasites from cattle and buffalo

Parasitology ◽  
1999 ◽  
Vol 118 (6) ◽  
pp. 541-551 ◽  
Author(s):  
N. E. COLLINS ◽  
B. A. ALLSOPP
Keyword(s):  
Genetic Recombination ◽  
Large Subunit ◽  
Small Subunit ◽  
Internal Transcribed Spacers ◽  
Rrna Genes ◽  
Gene Pools ◽  
Theileria Parva ◽  
Causative Agents ◽  
Internal Transcribed Spacer Sequences

We sequenced the rRNA genes and internal transcribed spacers (ITS) of several Theileria parva isolates in an attempt to distinguish between the causative agents of East coast fever and Corridor disease. The small subunit (SSU) and large subunit (LSU) rRNA genes from a cloned T. p. lawrencei parasite were sequenced; the former was identical to that of T. p. parva Muguga, and there were minor heterogeneities in the latter. The 5·8S gene sequences of 11 T. parva isolates were identical, but major differences were found in the ITS. Six characterization oligonucleotides were designed to hybridize within the variable ITS1 region; 93·5% of T. p. parva isolates examined were detected by probe TPP1 and 81·8% of T. p. lawrencei isolates were detected by TPL2 and/or TPL3a. There was no absolute distinction between T. p. parva and T. p. lawrencei and the former hybridized with fewer of the probes than did the latter. It therefore seems that a relatively homogenous subpopulation of T. parva has been selected in cattle from a more diverse gene pool in buffalo. The ITSs of both T. p. parva and T. p. lawrencei contained different combinations of identifiable sequence segments, resulting in a mosaic of segments in any one isolate, suggesting that the two populations undergo genetic recombination and that their gene pools are not completely separate.

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