Estimation of the amount of 5-methylcytosine in Drosophila melanogaster DNA by amplified ELISA and photoacoustic spectroscopy.

Achwal, Chhaya W.; Ganguly, P.; Chandra, H. Sharat

doi:10.1002/j.1460-2075.1984.tb01795.x

Cited by 66 publications

(38 citation statements)

References 26 publications

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“…The source of rapid deletion is unclear, particularly since it applies only to Drosophila DNA with simple sequences arranged serially and not to Drosophila DNA in general. Base modification by methylation is unlikely because N6-methyladenine, 5-methylcytosine, or other methylated bases occur rarely, if at all, in embryonic DNA of Drosophila (25,26). Single-stranded gaps, regions which might enhance recombination, are undetectable in satellite DNA preparations and no unusual structures are seen in electron microscopic examination of satellite DNA (unpublished results).…”

Section: --------C -------T---g-g--t--------------------------------*mentioning

confidence: 94%

Multiplicity of satellite DNA sequences in Drosophila melanogaster.

Lohe¹,

Brutlag²

1986

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

122

107

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Three Drosophila melanogaster satellite DNAs (1.672, 1.686, and 1.705 g/ml in CsCl), each containing a simple sequence repeated in tandem, were cloned in pBR322 as small fragments about 500 base pairs long. This precaution minimized deletions, since inserts of the same size as the fragments used for cloning were recovered in a stable form. A homogeneous tandem array of one sequence type usually extended the length of the insert. Eleven distinct repeat sequences were discovered, but only one sequence was predominant in each satellite preparation. The remaining classes were minor in amount. The repeat unit lengths were restricted to 5, 7, or 10 base pairs, with sequences closely related. Each sequence conforms to the expression (RRN),(RN)., where R is A or G. The multiplicity of simple repeated sequences revealed despite the small sample size suggests that numerous repeat sequences reside in heterochromatin and that particular rules apply to the structure of the repeating sequence. (10,11). Since the starting size of the purified satellite DNA in these experiments was about 10 kb, more than 95% of the satellite DNA insert had been deleted during propagation.In addition, many ofthese clones contained nonrepresentative DNA sequences and other alterations apparently introduced subsequent to cloning (unpublished observation). There were frequent interruptions in the periodicity of the repeat by additions or deletions and numerous base alterations. These aberrations were not seen when clones carrying inserts of the same size ranges as the starting material, and therefore showing no evidence for deletion, were sequenced (see Results).We investigated the instability of clones derived from the three simple satellite DNAs by varying the size of fragments used for cloning. When small DNA segments (==500 bp) were cloned in pBR322, fragments of the same size could be recovered from the plasmids although the efficiency of cloning was low. Clones were sequenced to verify the fidelity of cloning and to identify the repeating sequence. Although each of the 1.672, 1.686, and 1.705 satellites is comprised primarily of one simple sequence arranged in extremely homogeneous, tandem arrays, an unexpected finding was that numerous clones contained short repeating sequences different from the predominant type of repeat. These repeats differ by nucleotide changes only at certain positions of the repeat sequence and not at all in others. The results indicate that the complexity of repeated sequence types in heterochromatin is much greater than suggested by simply four major satellite DNAs and that certain rules govern the sequence permissible in a tandem array of simple repeats. MATERIALS AND METHODSCloning of Satellite DNAs. Total DNA was isolated from nuclei of D. melanogaster Oregon R embryos of average age 8 hr (12). Satellite DNAs were isolated in antibiotic/CsCl gradients and banded as single symmetrical peaks in the analytical ultracentrifuge (4). A partially purified preparation of the 1.690-g/ml satellite (1)

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Section: --------C -------T---g-g--t--------------------------------*mentioning

confidence: 94%

Multiplicity of satellite DNA sequences in Drosophila melanogaster.

Lohe¹,

Brutlag²

1986

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

122

107

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“…Initial studies performed in the 1980s produced conflicting results. 14,15 This organism lacks homologs of the mammalian DNA methyltransferase genes Dnmt1, Dnmt3a, or Dnmt3b but contains a gene encoding a homolog of Dnmt2 (also known as Mt2; NM_058127). The Drosophila genome also harbors a homolog of the mammalian methylated-CpG binding protein MBD2 (dMBD2/3).…”

Section: Dna Methylation In Insectsmentioning

confidence: 99%

The mysterious presence of a 5-methylcytosine oxidase in theDrosophilagenome

et al. 2013

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“…One explanation for this observation might be that the fraction of the site which is not cut within the nuclei is resistant by virtue of some chemical modification which renders it uncuttable by the enzyme. Though Drosophilu has little if any capacity to methylate its DNA (Achwal et al, 1984), we determined the extent of cutting at these restriction sites in naked genomic DNA. The result of the microdensitometry is given in Table 1.…”

Section: The Same Sites Ure Completely Cut In Naked D N Amentioning

confidence: 99%

Restriction enzymes permit quantitative determination of defined chromatin structures within the chromosome

Jack

Moritz

Cremer

1991

European Journal of Biochemistry

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Open chromatin structures, operationally defined as nuclease-hypersensitive sites, are frequently found spanning the controlling regions of genes and they may ensure that trans-acting factors have ready access to their genomic substrates. The rapidity and extent of induction of a gene may be dependent on the probability that its promoter is folded into an open structure. We show that restriction enzymes can be used to estimate the probability that a given promoter region is contained within a defined structure in the chromosome. In the case of the Drasophila major heat-shock-protein gene, we show that an individual promoter element is folded in an accessible form in at least 75% of embryonic chromosomes. This efficient maintenance of the hypersensitive region may be a necessary precondition for a rapid heat-shock response.

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Estimation of the amount of 5-methylcytosine in Drosophila melanogaster DNA by amplified ELISA and photoacoustic spectroscopy.

Cited by 66 publications

References 26 publications

Multiplicity of satellite DNA sequences in Drosophila melanogaster.

Multiplicity of satellite DNA sequences in Drosophila melanogaster.

The mysterious presence of a 5-methylcytosine oxidase in theDrosophilagenome

Restriction enzymes permit quantitative determination of defined chromatin structures within the chromosome

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