Enhancer
HOX D promoter
eRNA
HOTAIR
H3K27 Ac
H3K4me3
H3K27me3
Histone marks
A
B
Xist
X chromosome
X chromosome
Nuclear lamina membrane
Nuclear lamina membrane
Silenced
X chromosome
X chromosome
C
PTENP1
PTEN mRNA
Efficient translation
PTENP1
PTEN mRNA
Diminished translation
downregulation
D
E
Nuclear
speckle
miR-17
miR-21
miR-24
SRSF2
MALAT1
Normal cell
Cancer cell
Fig. 1 LncRNAs can scaffold chromatin-modifying complexes to mediate epigenetic silencing of
gene transcription: HOTAIR recruits the H3K4 demethylase complex LSD1-COREST and H3K27specific HMT PRC2 to the HOXD locus to silence it (a); eRNAs can allosterically activate
enhancer-bound HATs (b); lncRNAs can rearrange higher-order chromatin conformation: Xist
compacts the entire Xi into two silent megadomains and relocates them to the nuclear periphery
(c); lncRNAs known as ceRNAs can “sponge” miRNAs to upregulate the mRNA transcripts that
they target: PTENP1 sponges miRNAs that target PTEN transcripts (d); lncRNAs can regulate
splicing outcomes by sequestering splicing factors in subnuclear compartments, as MALAT1 can
sequester SRSF1 to nuclear speckles to restrict its availability to participate in splicing reactions (e)
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