Table 1.

Similarities and differences between miRNAs and lncRNAs

Characteristics	miRNA	lncRNAs
Size	Short (18 to 21 nucleotides)	>200 nucleotides
Primary mode of action	Negatively regulating the expression by complementary binding to target mRNAs and causing their degradation or inhibiting translation	Highly diverse, regulate gene expression by various mechanisms. Lnc-RNAs may work as  1. Signaling cues  2. Guides  3. Decoys  4. Scaffolds  5. miRNA sponges
Genomic location	-Exonic -Intergenic (between genes) -Intronic (embedded in a gene)	-Antisense RNA -LincRNA -Sense overlapping RNA -Sense intronic RNA - 3’ overlapping ncRNA
Secondary structure	Usually the precursor miRNA forms a hairpin structure	Forms simple to complex secondary structures 59, 60
Post-transcriptional processing	Typically produced as pri-miRNAs, which are processed by miRNA-processing enzymes (Drosha, DGCR8) and Dicer to generate pre-miR and mature miRNAs	Undergo post-transcriptional processing like mRNAs, i.e. 5’ capping, polyadenylation, and splicing
Computational gene target prediction	Relatively easy. Multiple bioinformatics tools/ prediction algorithms available that help to predict target genes	Difficult to predict. Not available.
Conservation between species	Relatively well conserved nucleotide sequences across species, although some species-specific miRNAs exist	Poorly conserved between species at the level of primary nucleotide sequences, but may have conserved secondary structures
Experimental gain-of-function strategies	miRNA mimics, over-expression plasmids, transgenic overexpression	over-expression plasmids, transgenic overexpression
Experimental loss-of-function strategies	Anti-miRs, antagomiRs, and morpholinos, genetic deletions	GapmeRs, genetic deletions or mutations