The “Fifth” RNA Nucleotide: A Role for Ribosomal RNA Pseudouridylation in Control of Gene Expression at the Translational Level - Biophysical Approaches to Translational Control of Gene Expression - page 273

Regulatory signals?
(e.g. growth factors, oncogenes)

?

Modified rRNA

ITAFs

H/ACA snoRNPs

NOP10

PUA
domain

Cell growth/proliferation

NHP2

Dyskerin

5'

Ψ

3'

Translation
control of
gene expression

ACA

Ψ

catalytc
domain

Tumor suppression
(OIS/apoptosis)

snoRNA

rRNA

hGAR1

Differentiation/Development

rRNA pseudouridylation

?

Other cis -acting
mRNA elements?

Other RNA substrates?
(e.g. mRNAs)

Frameshift signals

IRES elements

IRES element

3'

X XXY YYZ

5'

ORF 3'

5'

Slippery site Spacer Pseudoknot

Fig. 13.5 rRNA pseudouridylation fine-tunes control of gene expression at the translational level. Schematic diagram representing the possible mechanisms
by which pseudouridylation of rRNA may impinge on the translational control of gene expression. rRNA pseudouridylation is carried out by the H/ACA
snoRNP complex; however, the regulatory signals modulating this process remain poorly understood. The incorporation of Y residues ( red ) at specific sites on
rRNA affects the association of the ribosome with highly structured RNA elements including IRES sequences, programmed ribosomal frameshifting signals,
and may also affect the recruitment of additional cis -acting mRNA regulatory elements yet to be identified. Y residues on rRNA may affect the recruitment of
ITAFs and additional factors that enhance translation of specific mRNAs. Recent studies also suggest that other RNA substrates such as mRNA may also be
targeted for pseudouridylation by the H/ACA snoRNPs