Ordered distribution of modified bases in the DNA of a dinoflagellate

Steele, Robert E.; Rae, Peter M. M.

doi:10.1093/nar/8.20.4709

Cited by 35 publications

(22 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4). In agreement with previous studies, we found that these dinoflagellates contain 5-MeCyt and have replaced a substantial fraction of Thy with HOMeUra (10,11,19). Diplonema DNA also contained a spot that migrates at the position of 5-Me-dCMP (see below) whereas no DNA methylation was FIG.…”

Section: Resultssupporting

confidence: 92%

β- d -Glucosyl-hydroxymethyluracil is a conserved DNA modification in kinetoplastid protozoans and is abundant in their telomeres

Leeuwen¹,

Taylor²,

Mondragon³

et al. 1998

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

120

132

View full text Add to dashboard Cite

A BSTR ACTThe unusual DNA base ␤-D-glucosylhydroxymethyluracil, called ''J,'' replaces Ϸ0.5-1% of Thy in DNA of African trypanosomes but has not been found in other organisms thus far. In Trypanosoma brucei, J is located predominantly in repetitive DNA, and its presence correlates with the silencing of telomeric genes. Using antibodies specific for J, we have developed sensitive assays to screen for J in a range of organisms and have found that J is not limited to trypanosomes that undergo antigenic variation but is conserved among Kinetoplastida. In all kinetoplastids tested, including the human pathogens Leishmania donovani and Trypanosoma cruzi, J was found to be abundantly present in the (GGGTTA) n telomere repeats. Outside Kinetoplastida, J was found only in Diplonema, a small phagotrophic marine f lagellate, in which we also identified 5-MeCyt. Fractionation of Diplonema DNA showed that the two modifications are present in a common genome compartment, which suggests that they may have a similar function. Dinof lagellates appear to contain small amounts of modified bases that may be analogs of J. The evolutionary conservation of J in kinetoplastid protozoans suggests that it has a general function, repression of transcription or recombination, or a combination of both. T. brucei may have recruited J for the control of genes involved in antigenic variation.In the nuclear DNA of Trypanosoma brucei, Ϸ0.5-1% of Thy is replaced by the modified base ␤-D-glucosyl-hydroxymethyluracil (␤-gluc-HOMeUra) (1). This base that we call ''J'' was detected initially by 32 P-nucleotide postlabeling combined with twodimensional TLC (2D-TLC) (2), and we used this technique to show that approximately one-half of the cellular J is present in both strands of the telomeric (GGGTTA) n repeats (3). To map the location of J more precisely, we have generated antisera that immunoprecipitate J-containing duplex DNA and that detect this DNA with high sensitivity and specificity on dot blots (4). We have used these antisera to demonstrate that J is present in other repetitive DNA sequences but not in housekeeping genes or transcribed repeats (4). Moreover, we have shown that J is responsible for the blocked restriction sites that are present in silent telomeric variant surface glycoprotein (VSG) genes but not in actively transcribed VSG genes (4-6). This result has linked J to the transcriptional control of VSG genes.Thus far, J has been detected only in African trypanosome species that undergo antigenic variation (2). The availability of antibodies acting against J has prompted us to reinvestigate whether J is also present in other organisms. With anti-J-DNA immunoblots, approximately one J per 10 7 bases can be detected, which is Ϸ1,000-fold more sensitive than MATERIALS AND METHODSCells and DNA Analysis. DNA was derived from: T. brucei brucei (427); Trypanosoma congolense (WG81 and TSW13 bloodstream forms and WG81 procyclics); Trypanosoma vivax (Y58); Crithidia fasciculata (ϭ C. luciliae); Leishmania donovani (HU3); Leishmania tarentol...

show abstract

Section: Resultssupporting

confidence: 92%

β- d -Glucosyl-hydroxymethyluracil is a conserved DNA modification in kinetoplastid protozoans and is abundant in their telomeres

Leeuwen¹,

Taylor²,

Mondragon³

et al. 1998

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

120

132

View full text Add to dashboard Cite

show abstract

“…A fragment -2 kb in length is also found in the hybridization patterns of all of the DNAs (Fig. IB), and has also been shown to hybridize only with 17s rRNA in WHd (24). It is slightly smaller in WHd/PS rDNA than in the rDNA of the other isolates.…”

Section: Resultsmentioning

confidence: 78%

“…The 1.35 kb fragment present in the WHd strain and the Puget Sound isolate (Fig. IB) has been shown to contain only 24s RNA coding sequences (24). A fragment of this size is absent from the DNAs of the other isolates, but they have hybridizing Hind 111 fragments of sizes not found in WHdlPS rDNA.…”

Section: Resultsmentioning

confidence: 88%

“…IB). It hybridizes only with 17s ribosomal RNA in WHd (24). The fragment is probably the same in all the isolates, being a highly conserved part of the 17s RNA coding region.…”

Section: Resultsmentioning

confidence: 93%

“…It is slightly smaller in WHd/PS rDNA than in the rDNA of the other isolates. This situation likely reflects heterogeneity in spacer DNA sequences flanking the 17s coding sequence (24). The 1.35 kb fragment present in the WHd strain and the Puget Sound isolate (Fig.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of DNAs of Crypthecodinium cohnii‐like Dinoflagellates from Widespread Geographic Locations*

Steele

Rae

1980

The Journal of Protozoology

Self Cite

View full text Add to dashboard Cite

SYNOPSIS. . We have examined various properties of DNAs from 7 dinoflagellate isolates of wide geographic distribution; all of the isolates are superficially indistinguishable from a laboratory strain of Crypthecodinium cohnii originally isolated at Woods Hole, Massachusetts (WHd strain). Two isolates, one from Puerto Rico and the other from Honduras, are clearly distinguishable from WHd and the other isolates by their DNA buoyant density values. WHd and the other 5 isolates we have examined are indistinguishable from one another in terms of DNA buoyant densities and melting temperatures. The relationship among the various isolates, including WHd, were evaluated at a finer level through restriction endonuclease cleavage and molecular hybridization to compare ribosomal RNA gene structure in the several DNAs. All the isolates could be further categorized by this method, the patterns of restriction endonuclease cleavage of ribosomal RNA genes in the isolates paralleling exactly their sexual compatibilities established from breeding experiments by Beam & Himes. The DNAs were also treated with a restriction endonuclease sensitive to the presence of the modified base 5-methylcytosine. In all isolates, cytosine residues in both total DNA and DNA specifically containing the ribosomal RNA genes were found to be extensively methylated, as was previously shown for the WHd strain.

show abstract

Unusual Features of Dinokaryon, the Enigmatic Nucleus of Dinoflagellates

Fukuda

Suzaki

2015

Marine Protists

View full text Add to dashboard Cite

Ordered distribution of modified bases in the DNA of a dinoflagellate

Cited by 35 publications

References 34 publications

β- d -Glucosyl-hydroxymethyluracil is a conserved DNA modification in kinetoplastid protozoans and is abundant in their telomeres

β- d -Glucosyl-hydroxymethyluracil is a conserved DNA modification in kinetoplastid protozoans and is abundant in their telomeres

Comparison of DNAs of Crypthecodinium cohnii‐like Dinoflagellates from Widespread Geographic Locations*

Unusual Features of Dinokaryon, the Enigmatic Nucleus of Dinoflagellates

Contact Info

Product

Resources

About