Pseudouridine

Pseudouridine (abbreviated by the Greek letter psi- Ψ or the letter Q) is an isomer of the nucleoside uridine in which the uracil is attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond. (In this configuration uracil is sometimes referred to as 'pseudouracil'.) It is the most prevalent of the over one hundred different modified nucleosides found in RNA. Ψ is found in all species and in many classes of RNA. Ψ is formed by enzymes called Ψ synthases, which post-transcriptionally isomerize specific uridine residues in RNA in a process termed pseudouridylation. Currently, about ∼ 9500 pseudouridine (Ψ) modifications have been identified in mammals and yeast and deposited in RMBase database. Pseudouridine (abbreviated by the Greek letter psi- Ψ or the letter Q) is an isomer of the nucleoside uridine in which the uracil is attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond. (In this configuration uracil is sometimes referred to as 'pseudouracil'.) It is the most prevalent of the over one hundred different modified nucleosides found in RNA. Ψ is found in all species and in many classes of RNA. Ψ is formed by enzymes called Ψ synthases, which post-transcriptionally isomerize specific uridine residues in RNA in a process termed pseudouridylation. Currently, about ∼ 9500 pseudouridine (Ψ) modifications have been identified in mammals and yeast and deposited in RMBase database. It is commonly found in tRNA, associated with thymidine and cytosine in the TΨC arm and is one of the invariant regions of tRNA. The function of it is not very clear, but it is expected to play a role in association with aminoacyl transferases during their interaction with tRNA, and hence in the initiation of translation. Recent studies suggest it may offer protection from radiation.