Disease relevance of Isopentenyladenosine

• Readthrough and suppression of nonsense codons was compared in Escherichia coli strains with and without a miaA mutation, which confers a loss of the isopentenyladenosine modification in transfer RNA [1].

High impact information on Isopentenyladenosine

• Selective inhibition of selenocysteine tRNA maturation and selenoprotein synthesis in transgenic mice expressing isopentenyladenosine-deficient selenocysteine tRNA [2].
• The consequences on selenoprotein biosynthesis of overexpressing either the wild type or a mutant tRNA([Ser]Sec) lacking the modified base, isopentenyladenosine, in its anticodon loop were examined by introducing multiple copies of the corresponding tRNA([Ser]Sec) genes into the mouse genome [2].
• MOD5 translation initiation sites determine N6-isopentenyladenosine modification of mitochondrial and cytoplasmic tRNA [3].
• tRNA-isopentenyltransferase (tRNA-IPT) catalyses the addition of N6-isopentenyladenosine (i6A) on residue 37 of tRNA molecules that bind codons starting with uridine [4].
• To determine the presence and identity of isopentenyladenosine-containing transfer RNAs (tRNAs) in a mammalian cell line, we adopted a novel method to isolate, clone and sequence these RNAs [5].

Biological context of Isopentenyladenosine

• These results indicate that the biosynthesis of the 2-methylthio derivative of isopentenyladenosine may occur in a sequential manner, i.e., thiolation of isopentenyladenosine followed by methylation [6].
• Activation of caspase-like proteases and induction of apoptosis by isopentenyladenosine in tobacco BY-2 cells [7].

Anatomical context of Isopentenyladenosine

• A mutation in the yeast nuclear gene MOD5 drastically reduces the biosynthesis of the modified base isopentenyladenosine in tRNAs located in different cellular compartments: the mitochondria and the nucleus or cytoplasm [8].
• N6-isopentenyladenosine affects cAMP-dependent microfilament organization in FRTL-5 thyroid cells [9].
• Adding sufficient iron to saturate the iron-binding capacity of the lactoferrin present in milk and colostrum reversed these changes which are probably due to a failure to methylthiolate the isopentenyladenosine [10].
• Here we investigated the anti-proliferative effect of N6-isopentenyladenosine (i6A), an adenosine and isoprenoid derivative, in a thyroid cell system, FRTL-5 wild-type, and K-ras transformed KiMol cells [11].
• Effects of norepinephrine and isopentenyladenosine on Na+/Ca2+ exchange currents in isolated guinea pig ventricular myocytes [12].

Associations of Isopentenyladenosine with other chemical compounds

• Electron spin resonance (ESR) spectra of yeast tRNATyr. spin-labelled in the isopentenyladenosine residue adjacent to the anticodon, were measured as a function of temperature at various spermine/tRNA ratios [13].
• This study reports the effects of thidiazuron (TDZ) on the endogenous levels of indoleacetic acid (IAA), zeatin, zeatin riboside ([9R]Z), isopentenyladenine and isopentenyladenosine ([9R]iP) as well as structural changes in the apical meristem of Dendrobium Second Love shoots during flower induction and initial development in vitro [14].
• In intact mitochondria, the inhibition by iP and BA significantly increased, I50 being 50 and 250 microM, respectively, but that by zeatin and iPA decreased [15].

Gene context of Isopentenyladenosine

• The antisuppressor strain sin1 of Schizosaccharomyces pombe lacks the modification isopentenyladenosine in transfer RNA [16].
• Results from in vivo feeding of chloronemal tissue with tritiated isopentenyladenosine suggest that adenosine kinase plays an important role in the conversion of cytokinins towards their nucleotides in Physcomitrella [17].
• Plants of the pga22 mutant accumulated at remarkably higher levels of isopentenyladenosine-5'-monophosphate and isopentenyladenosine when analyzed by mass spectrometry, suggesting that AtIPT8/PGA22 is a functional IPT that may direct the biosynthesis of cytokinins in planta via an isopentenyladenosine-5'-monophosphate-dependent pathway [18].
• With the use of PMR the ribose conformations have been studies in the temperature range -60 to +40 degrees C in ND3 solutions of adenosine (A), guanosine (G), inosine (I), xanthsine (X), purineriboside (PR), 2-aminopurineriboside (2amPR), N6-isopentenyladenosine (N6ipA), 8-bromoadenosine (iA), and isopropylideneguanosine (iG) [19].

Analytical, diagnostic and therapeutic context of Isopentenyladenosine

• Antibodies specific for isopentenyladenosine (i6A) were employed to investigate the efficacy of various immunoadsorbents with respect to immobilization of antibody protein and with respect to their ability to bind i6A-containing tRNAs [20].
• A sensitive radioimmunoassay for isopentenyladenosine [21].

References