Queuine is incorporated into brain transfer RNA

Abstract

Pig brain tRNA was assayed for the presence of queuosine in the first position of the anticodon for each of the Q-family of tRNAs (aspartyl, asparaginyl, histidyl and tyrosyl). The brain tRNA was aminoacylated with each of the four amino acids and the aminoacylated tRNA's analyzed by RPC-5 chromatography. The results of this study show that for all four tRNAs of the family, queuine is substituted for guanine in virtually 100% of the anticodons. Therefore, it can be concluded that queuine is able to cross the blood-brain barrier and that brain contains guanine-queuine tRNA transglycosylase, the enzyme responsible for the excision of guanine from the original transcripts of these tRNAs and insertion of queuine. The determination of whether the tRNA contained queuine was made from the elution profile of the RPC-5 chromatograms and the results confirmed by a change in the RPC-5 elution profile when the tRNAs were reacted with BrCN or NaIO4.

Queuine, a bacterial-derived hypermodified nucleobase, shows protection in in vitro models of neurodegeneration

“…Queuine is a pyrrolopyrimidine-containing analog of guanine ( Fig 1 ) that is exclusively synthesized by bacteria and found in most eukaryotes, including humans who acquire queuine from their own gut microbiota and a diet containing this bacterial-derived molecule [ 11 ]. Queuine produced by the gut microbiota is salvaged by humans through their gut epithelium and is distributed to a wide range of tissues including the brain where it is enriched [ 12 ]. Queuine is incorporated into the wobble position (nucleoside 34) of cytoplasmic and mitochondrial transfer RNAs (tRNAs) containing a G 34 U 35 N 36 (N = any nucleotide) anticodon sequence [ 13 , 14 ].…”

Isotope‐Based Analysis of Modified tRNA Nucleosides Correlates Modification Density with Translational Efficiency

“…Furthermore, while levels of queuosine (Q) generally fit the overall trend, this nucleoside has unexpectedly high levels in brain tissue both in mouse and pig, suggesting a more complex specialized role in those tissues. [15]…”

Queuine, a bacterial derived hypermodified nucleobase, shows protection inin vitromodels of neurodegeneration

“…Queuine is a pyrrolopyrimidine containing analog of guanine that is exclusively synthesized by bacteria and found in most eukaryotes, including humans who acquire queuine from their own gut microbiota and a diet containing this bacterial derived molecule [11]. Queuine produced by the gut microbiota is salvaged by humans through their gut epithelium and is distributed to a wide range of tissues including the brain where it is enriched [12]. Queuine is incorporated into the wobble position (nucleoside 34) of cytoplasmic and mitochondrial transfer RNAs (tRNAs) containing a G34U35N36 (N = any nucleotide) anticodon sequence [13,14].…”