Robert S Sabatini

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RNA editing in Trypanosoma brucei results in the addition and deletion of uridine residues within several mitochondrial mRNAs. Editing is thought to be directed by guide RNAs and may proceed via a chimeric guide RNA/mRNA intermediate. We have previously shown that chimera-forming activity sediments with 19 S and 35-40 S mitochondrial ribonucleoprotein(More)
In 1993, a new base, beta-d-glucopyranosyloxymethyluracil (base J), was identified in the nuclear DNA of Trypanosoma brucei. Base J is the first hypermodified base found in eukaryotic DNA. It is present in all kinetoplastid flagellates analyzed and some unicellular flagellates closely related to trypanosomatids, but it has not been found in other protozoa(More)
Kinetoplastid RNA editing consists of the addition or deletion of uridines at specific sites within mitochondrial mRNAs. This unusual RNA processing event is catalyzed by a ribonucleoprotein (RNP) complex that includes editing site-specific endoribonuclease, RNA ligase and terminal uridylnucleotidyl transferase (Tutase) among its essential enzymatic(More)
Base J is a hypermodified DNA base localized primarily to telomeric regions of the genome of Trypanosoma brucei. We have previously characterized two thymidine-hydroxylases (TH), JBP1 and JBP2, which regulate J-biosynthesis. JBP2 is a chromatin re-modeling protein that induces de novo J-synthesis, allowing JBP1, a J-DNA binding protein, to stimulate(More)
Trypanosomatids contain an unusual DNA base J (beta-d-glucosylhydroxymethyluracil), which replaces a fraction of thymine in telomeric and other DNA repeats. To determine the function of base J, we have searched for enzymes that catalyze J biosynthesis. We present evidence that a protein that binds to J in DNA, the J-binding protein 1 (JBP1), may also(More)
DNA from Kinetoplastida contains the unusual modified base beta-D-glucosyl(hydroxymethyl)uracil, called J. Base J is found predominantly in repetitive DNA and correlates with epigenetic silencing of telomeric variant surface glycoprotein genes in Trypanosoma brucei. We have now identified a protein in nuclear extracts of bloodstream stage T.brucei that(More)
BACKGROUND Endosseous dental implants with rough surfaces have been designed to improve early healing, especially in areas of poor bone or insufficient bone quantity. The aim of this study was to histomorphometrically assess the bone-to-implant contact on 3 different rough-surfaced implants following guided bone regeneration. METHODS Mandibular premolars(More)
Genomic DNA of African trypanosomes contains a hypermodified thymidine residue termed base J (beta-d-glucosyl-HOMedU). This modified base is localized primarily to repetitive DNA, namely the telomeres, and is implicated in the regulation of antigenic variation. The base is synthesized in a two-step pathway. Initially, a thymidine residue in DNA is(More)
Synthesis of the modified thymine base beta-D-glucosyl-hydroxymethyluracil, or J, within telomeric DNA of Trypanosoma brucei correlates with the bloodstream-form-specific epigenetic silencing of telomeric variant surface glycoprotein genes involved in antigenic variation. The mechanism of developmental and telomeric-specific regulation of J synthesis is(More)
Unlike other eukaryotes, the protein-coding genes of Trypanosoma cruzi are arranged in large polycistronic gene clusters transcribed by polymerase II (Pol II). Thus, it is thought that trypanosomes rely solely on posttranscriptional processes to regulate gene expression. Here, we show that the glucosylated thymine DNA base (β-d-glucosyl-hydroxymethyluracil(More)