Telomeric localization of the modified DNA base J in the genome of the protozoan parasite Leishmania

Base J or β-D-glucosylhydroxymethyluracil is a DNA modification replacing a fraction of thymine in the nuclear DNA of kinetoplastid parasites and of Euglena. J is located in the telomeric sequences of Trypanosoma brucei and in other simple repeat DNA sequences. In addition, J was found in the inacti...

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Veröffentlicht in:Nucleic acids research 2007-04, Vol.35 (7), p.2116-2124
Hauptverfasser: Genest, Paul-André, ter Riet, Bas, Cijsouw, Tony, van Luenen, Henri G.A.M, Borst, Piet
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Sprache:eng
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Zusammenfassung:Base J or β-D-glucosylhydroxymethyluracil is a DNA modification replacing a fraction of thymine in the nuclear DNA of kinetoplastid parasites and of Euglena. J is located in the telomeric sequences of Trypanosoma brucei and in other simple repeat DNA sequences. In addition, J was found in the inactive variant surface glycoprotein (VSG) expression sites, but not in the active expression site of T. brucei, suggesting that J could play a role in transcription silencing in T. brucei. We have now looked at the distribution of J in the genomes of other kinetoplastid parasites. First, we analyzed the DNA sequences immunoprecipitated with a J-antiserum in Leishmania major Friedlin. Second, we investigated the co-migration of J- and telomeric repeat-containing DNA sequences of various kinetoplastids using J-immunoblots and Southern blots of fragmented DNA. We find only ~1% of J outside the telomeric repeat sequences of Leishmania sp. and Crithidia fasciculata, in contrast to the substantial fraction of non-telomeric J found in T. brucei, Trypanosoma equiperdum and Trypanoplasma borreli. Our results suggest that J is a telomeric base modification, recruited for other (unknown) functions in some kinetoplastids and EUGLENA:
ISSN:0305-1048
1362-4962
DOI:10.1093/nar/gkm050