Fig. 1

LncRNAs exert functions through a variety of signaling pathways in the human body. a miRNA sponge. MIAT, acting as a molecular sponge, binds to miR-150-5p, thereby upregulating the level of miR-150-5p target gene. b mRNA stability/degradation. LncRNA binding to mRNA may stabilize (e.g., BACE1-AS prevents miRNA-induced repression of BACE1 transcript) or decay target transcripts. c Translation. LncRNAs promote (like antisense Uchl) or repress (like lincRNA-p21) translation of transcripts. d Alternative splicing. MALAT1 acting as scaffold for SR proteins regulates pre-mRNA alternative splicing. e Transcription. PACER (lethe and p50-associated Cox-2 extragenic RNA) directly interacts with different subunits of NF-κB, thus preventing it from binding to the Cox-2 promoter. THRIL, together with heterogeneous nuclear ribonucleoproteins (hnRNPs), acts as RNA-protein complex and binds to TNF-α promoter and induces TNF-α expression. f Epigenetic imprinting. Working models of gene regulation by cis- (a) and trans-acting (b) lncRNAs. LncRNAs, such as Xist/RepA, Air, HOTAIR, and Kcnq1ot1, may act as docking platforms for the chromatin remodeling complex, polycomb repressive complex (PRC2) 2, which methylates histone H3 at lysine 27 (H3K27me3), leading to a repression or gain of transcriptional activity, respectively