[29] Analysis of repeating DNA sequences by reassociation

Britten, Roy J.; Graham, Dale E.; Neufeld, Berney R.

doi:10.1016/0076-6879(74)29033-5

Cited by 924 publications

(527 citation statements)

References 34 publications

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“…The total proportion of applied DNA recovered from the hydroxyapatite was 90 per cent and 83 per cent respectively. The differences between the two isolations may be due to different flow rates and bed volumes of the columns used (Britten et al, 1974). Thermal dissociation profiles for total wheat DNA and the C0t 10-2 isolates in TE ( fig.…”

Section: Resultsmentioning

confidence: 99%

Chromosomal locations of highly repeated DNA sequences in wheat

Gerlach

Peacock

1980

Heredity

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SUMMARYC0t l0 DNA was isolated from hexaploid wheat Tr-iticum aestivum cv. Chinese Spring by hydroxyapatite chromatography (70°C in 0l2 M phosphate buffer). The higher Tm of the Cot 10-2 DNA compared with total wheat DNA suggested that it was relatively GC rich and contained well matched hybrids.In situ hybridisation using wheat species of different ploidy levels located major sites of the C0t l0-DNA on the B genome chromosomes. More than one particular highly repeated sequence is located in these sites. Other chromosomal locations could be visualised by heating in situ hybridisation reactions before renaturation. This was attributed to the availability for hybridisation both of chromosomal sequences additional to those normally available after acid denaturation of cytological preparations and to single stranded cRNA molecules which were otherwise present as double stranded structures.

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Section: Resultsmentioning

confidence: 99%

Chromosomal locations of highly repeated DNA sequences in wheat

Gerlach

Peacock

1980

Heredity

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“…On passage over a HAP column, 10.9% of the tracer bound. Of this, about 6.4% is attributed to renatured tracer (a [3H]DNA Cot of 50 M-sec was generated during the reaction, and the tracer was 70% reactive), leaving 4.5% nRNA-DNA hybrid (the expected hybrid yield was 0.7 X 6% or 4.2%).…”

Section: Resultsmentioning

confidence: 99%

Distinct single-copy sequence sets in sea urchin nuclear RNAs.

Ernst¹,

Britten²,

Davidson³

1979

Proc. Natl. Acad. Sci. U.S.A.

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The purpose of this study was to determine whether nuclear RNAs (nRNA) of sea urchin embryos and adult tissues contain identical or partially distinct sets of single-copy sequence transcripts. A DNA tracer was prepared consisting mainly of sequences absent from gastrula nRNA; 3.6% of this tracer reacted with adult intestine nRNA but not with gastrula nRNA. The existence of a differentially transcribed DNA fraction was verified by its partial purification and rehybridization to intestine and gastrula nRNAs. About one-third of the genomic single-copy sequence is represented in both nRNAs, or about 2 x 108 nucleotides. The differentially transcribed portion of the single-copy genome identified in this work includes about 3.5 X 107 nucleotides. Recent measurements indicate that the nuclear RNAs (nRNAs) of several sea urchin embryo stages and adult tissues are of approximately equal sequence complexity. About a third of the single-copy DNA sequence is represented in the nRNAs of blastula (1), gastrula (2, 3), and pluteus (1) embryos and of previtellogenic ovarian oocytes (4) and adult intestine (5). Kleene and Humphreys (1) showed in addition that the single-copy sequence sets of blastula and pluteus nRNAs are largely overlapping. They concluded that with respect to single-copy sequence content, these nRNAs are in fact identical.Complete overlap in the single-copy sequence sets represented in diverse nRNAs would be paradoxical. The implication is that in the sea urchin differentiation need not be accompanied by alteration in the regions of the genome transcribed into nRNAs of typical prevalence. There are several reasons to question the conclusion that sea urchin nRNAs are identical. Scheller et al. (6) found recently that gastrula and adult intestine nRNAs differ strikingly in the representation of a number of repetitive sequence families. In the genome, these repetitive sequences are in general interspersed with single-copy sequence [ref. 7, and unpublished MATERIALS AND METHODS Preparation of Nuclear RNAs. Gastrula. Strongylocentrotus purpuratus were spawned, the eggs were fertilized, and the embryos were grown for 36 hr to the gastrula stage. nRNA was isolated as described earlier (6).Intestine. The intestine was removed from adult sea urchins, rinsed in seawater/EGTA [ethylene glycol-bis(,B-aminoethyl ether)-N,N,N',N'-tetraacetic acid] and lysed on ice in 50 mM Tris (pH 8.0), 5 mM magnesium chloride, 50 mM ammonium chloride, 5 mM EGTA, and 1% Triton X-100. Nuclei were pelleted through a 0.5 M sucrose cushion and the RNA was extracted as described earlier (5).Ovary. Nuclei were isolated from ovaries that contained previtellogenic oocytes and a high vitellogenic oocyte content, and the RNA was extracted by the methods of .Preparation of Labeled Single-Copy DNA. Single-copy DNA was renatured to 10-20 times the COtl/2 (moles of nucleotide liter-l sec) to form hyperpolymers (7,8). The DNA was labeled in vitro by the "gap translation" method with Escherichia coli polymerase 1 (8, 9). The single-copy tracer ...

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“…Until now, only three species have been established within the genus. Ureaplasma urealyticum was isolated originally from a patient with nongonococcal urethritis (2), Ureaplasma diversum was isolated from the lungs of cattle with pneumonia (ll), and Ureaplasma gallorale was isolated from the oropharynges of healthy chickens (16). There are at least 14 serovars of U .…”

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Ureaplasma felinum sp. nov. and Ureaplasma cati sp. nov. Isolated from the Oral Cavities of Cats

Harasawa

Imada

Ito

et al. 1990

International Journal of Systematic Bacteriology

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Seven ureaplasma strains isolated from the oral cavities of domestic cats (Felis domestica) were characterized and compared with the type strains of the three previously established species of this genus, Ureaplasma urealyticum (humans), Ureaplasma diversum (cattle), and Ureaphsma gallorule (chickens). The feline strains hydrolyzed urea but not arginine or glucose, were membrane bound, lacked cell walls, passed through 0.45-pm membrane filters, required cholesterol for growth, and formed minute (15-to 140-pm) colonies on agar medium. The seven feline strains fell into two distinct groups based on (i) their antigenic properties (determined by using the metabolism and growth inhibition and indirect immunoperoxidase procedures), (ii) their genomic properties (determined by using DNA-DNA hybridization and DNA cleavage pattern procedures), and (iii) their polypeptide profiles (determined by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses). Based on these properties, the two feline groups were unrelated to each other or to the three previously established species, and each group represents a distinct Ureaplasma species. Thus, we propose that ureaplasmas with these phylogenetic and genomic properties be given taxonomic status as Ureaplasma felinum and Ureaplasma cati, with strain FT2-B (= ATCC 49229 = NCTC 11709) and strain F2 (= ATCC 49228 = NCTC 11710) as the type strains, respectively.The genus Ureaplasma belongs to the family Mycopfasmataceae and is comprised of organisms that hydrolyze urea. Ureaplasmas are widely distributed in nature and colonize most animal species that have been examined, including humans (26, 27), nonhuman primates (39, cattle (12, 34), sheep (22), goats (6), dogs (39, cats (31), mink (3, raccoon dogs (15), pigs (29), and birds (28). They are also responsible for a number of diseases of humans and animals (6, 26). Until now, only three species have been established within the genus. Ureaplasma urealyticum was isolated originally from a patient with nongonococcal urethritis (2), Ureaplasma diversum was isolated from the lungs of cattle with pneumonia (ll), and Ureaplasma gallorale was isolated from the oropharynges of healthy chickens (16). There are at least 14 serovars of U . urealyticum, three serovars of U . diversum, and one serovar of U . gallorale.Ureaplasma strains isolated from domestic cats (Felis domestica) have been reported previously to be unrelated to and distinct from the three previously established species based on their antigenic and genomic properties (7,9,10,17, 19,20). In addition, we have reported that the G+C contents of DNAs from strains which belong to the two species proposed in this paper are 27.9 mol% (13) and 28.1 mol% (7); these contents are within the range of values (26.9 to 31.6 mol%) reported for the previously established species. Based on the data reported previously and in this paper, we believe that each of the two feline ureaplasma groups merits taxonomic classification as a new species, and we report here further characterizati...

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[29] Analysis of repeating DNA sequences by reassociation

Cited by 924 publications

References 34 publications

Chromosomal locations of highly repeated DNA sequences in wheat

Chromosomal locations of highly repeated DNA sequences in wheat

Distinct single-copy sequence sets in sea urchin nuclear RNAs.

Ureaplasma felinum sp. nov. and Ureaplasma cati sp. nov. Isolated from the Oral Cavities of Cats

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