High impact information on Oxytricha

• The beta subunit of Oxytricha telomere-binding protein promotes G-quartet formation by telomeric DNA [1].
• The Oxytricha proteins are not simply C4A4-binding proteins [2].
• Internal sequences are eliminated from genes during macronuclear development in the ciliated protozoan Oxytricha nova [3].
• Modulation of telomerase activity by telomere DNA-binding proteins in Oxytricha [4].
• The 4.1 kbp TBE1 elements of Oxytricha fallax and Oxytricha trifallax are deduced to transpose into a centrisymmetric target, CAnTG, and to duplicate the central AnT [5].

Biological context of Oxytricha

• Reordering of nine exons is necessary to form a functional actin gene in Oxytricha nova [6].
• In the hypotrichous ciliate Oxytricha nova all of the macronuclear DNA is in the form of low molecular weight, gene-sized molecules with an average size of 2,200 base pairs [7].
• We sequenced eRF1 from four ciliates: B. americanum, a heterotrich that independently derived the same eRF1 specificity as Euplotes, and three spirotrichs, Stylonychia lemnae, S. mytilus, and Oxytricha trifallax, that independently derived the same genetic code as Tetrahymena (UAR --> glutamine) [8].
• Excision of the approximately 150 000 IESs from a haploid germline genome in Oxytricha nova requires approximately 150 000 recombinant events [9].
• Binding linkage in a telomere DNA-protein complex at the ends of Oxytricha nova chromosomes [10].

Anatomical context of Oxytricha

• An enzymatic activity in crude extracts of macronuclei from the hypotrichous ciliate Oxytricha nova catalyzes the synthesis of RNA consisting of (C4A4)n using an oligodeoxynucleotide template of the telomeric sequence (dG4T4)n. Single-stranded (dG4T4)n is an effective template if it has a random sequence at its 5' end [11].

Associations of Oxytricha with chemical compounds

• Presence of the 5' thymidine tail preceding the Oxytricha telomeric repeat has no apparent effect on the hairpin secondary structure [12].
• This complex is between a dimeric antiparallel G-quadruplex formed from the Oxytricha nova telomeric DNA sequence d(GGGGTTTTGGGG), and a di-substituted aminoalkylamido acridine compound [13].
• The unit repeat in the protozoan Oxytricha with the cluster dT4G4 can form structures containing tetrads of guanine residues, referred to G4 DNA, in the presence of metal ions such as Na+ or K+ [14].
• The rapid exchange of thymine N3 imino sites indicates that thymine quartets are not stabilized in Oxytricha quadruplexes [15].
• During the purification of another Cd-linking compound, we were able to demonstrate that the H protein precursor of glycine cleavage is present in Oxytricha [16].

Gene context of Oxytricha

• POT1 belongs to a family of oligonucleotide-binding (OB)-fold-containing proteins that include Oxytricha nova TEBP, Cdc13, and spPot1, which specifically recognize telomeric single-stranded DNA (ssDNA) [17].
• We also demonstrate that a fusion protein consisting of the N-terminal region of Cdc13 and the C-terminal region of Stm1 (which shows similarity to the beta-subunit of the telomere binding complex in Oxytricha) could complement a cdc13 disruptant [18].
• Native telomeric chromatin isolated from Oxytricha contains both types of complexes [19].
• Mobile elements bounded by C4A4 telomeric repeats in Oxytricha fallax [20].
• Polymerase chain reaction analysis of micronuclear DNA of the related species, Oxytricha trifallax, shows that the actin gene has an unorthodox arrangement in this species also [6].

Analytical, diagnostic and therapeutic context of Oxytricha

• Using Raman spectroscopy, we have determined the dependence of the interquadruplex equilibrium of the telomeric repeat of Oxytricha nova, upon solution concentrations of Na+ and K+ [21].

References