Arrangement of coding and non-coding sequences in the DNA molecules coding for rRNAs in Oxytricha sp.

Swanton, Marshal T.; Greslin, Arthur F.; Prescott, David M.

doi:10.1007/bf00329545

Cited by 75 publications

(50 citation statements)

References 26 publications

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“…nova, S. lemnae, and E. aediculatus were grown as described previously (Swanton et al 1980) under nonsterile conditions with Chlorogonium as the food source.…”

Section: Growth Of Ciliatesmentioning

confidence: 99%

Telomerase RNAs of different ciliates have a common secondary structure and a permuted template.

Lingner¹,

Hendrick²,

Cech³

1994

Genes Dev.

184

220

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Telomerase is composed of protein and RNA. The RNA serves as a template for telomere DNA synthesis and may also be important for enzyme structure or catalysis. We have used the presence of conserved sequence elements in the promoter and template regions to amplify by PCR the telomerase RNA genes from six different hypotrichous ciliates: Oxytricha nova, Oxytricha trifallax, Stylonychia mytilis, Stylonychia lemnae, Enplotes aedicalatns, and Euplotes eurystomns. RNaseH cleavage of the O. nova RNA in extracts by use of a complementary oligonucleotide leads to loss of telomerase activity, supporting the identification. Primary sequence and biochemical experiments suggest that the templates of Oxytricha and Stylonychia are circularly permuted relative to that of E. aediculatns. On the basis of the pause sites, the former two add G4T4 during a single primer elongation cycle, whereas E. aedicalatus adds G3T4G. The only primary sequence element outside the template that is conserved between these phylogenetically distant telomerase RNAs is the sequence 5'-(C)UGUCA-3', which precedes the template regions by exactly two bases. We propose a common secondary structure model that is based on nucleotide covariations, a model which resembles that proposed previously for tetrahymenine telomerase RNAs.

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“…nova, S. lemnae, and E. aediculatus were grown as described previously (Swanton et al 1980) under nonsterile conditions with Chlorogonium as the food source.…”

Section: Growth Of Ciliatesmentioning

confidence: 99%

Telomerase RNAs of different ciliates have a common secondary structure and a permuted template.

Lingner¹,

Hendrick²,

Cech³

1994

Genes Dev.

184

220

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“…Oxytricha nova was grown in nonsterile culture using live Chlorogonium as the food source (Swanton et al 1980a). Macronuclei were isolated essentially as described by Swanton et al (1980a).…”

Section: Culturing Of Oxytricha Nova and Isolation Of Macronucleimentioning

confidence: 99%

“…Macronuclei were isolated essentially as described by Swanton et al (1980a). The following protease inhibitors were included in the isolation buffers: 0.1 mM phenylmethanesulfonyl fluoride (PMSF), 0.1 rn~ tosylphenylalanine chloromethylketone {TPCK), and 1.0 mM p-chloromercuribenzenesulfonic acid (PCMBS).…”

Section: Culturing Of Oxytricha Nova and Isolation Of Macronucleimentioning

confidence: 99%

Telomeric DNA-protein interactions of Oxytricha macronuclear DNA.

Price¹,

Cech²

1987

Genes Dev.

150

167

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Telomeres of Oxytricha macronuclear chromatin exist as discrete nonnucleosomal DNA-protein complexes, each of which encompasses the terminal 100-150 bp of a macronuclear DNA molecule. We have used chemical and nuclease footprinting to examine the internal structure of these telomeric complexes. Remarkably saltstable DNA-protein interactions result in methylation-protection of specific guanine residues in the 3'-terminal T+G4T+G4 tail. The methylation pattern seen in vivo and in isolated macronuclei is reconstituted in vitro when purified 55-kD and 43-kD telomere proteins are added to purified macronuclear DNA. Very different interactions are observed between protein and DNA within the region -45-135 bp from the 5' terminus. The DNase I cleavage pattern indicates that this DNA lies on the outside surface of protein but is not part of a nucleosome. Our data suggest that the telomeric complexes have two structural domains characterized by their dissimilar DNA-protein interactions. We propose that functionally equivalent telomeres from other organisms could be accommodated in a similar telomeric chromatin structure.

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“…Genes for tRNAs, histories, and other proteins always occur in given sized molecules. The gene coding for 19S, 26S, and 5.8S rRNAs is 7100 BP long (12); it is differentially amplified compared to other genes, and the greater copy number is visible as a distinct band in an electrophoretic gel ( Figure 3).…”

Section: Properties Of Macronuclear Dna Moleculesmentioning

confidence: 99%