1.1 LncRNA
LncRNAs, longer than 200 nt, stimulate or inhibit transcription at the
transcriptional level, influence mRNA splicing, editing, translation, or
stability at the post-transcriptional level, and performing epigenetic
regulation[2]. As reside in various cells and subcellular
localizations, different lncRNAs serve diverse activities at different
times. The following categories can be determined by where they are
located on coding genes: 1) Intergenic (has no overlap with
protein-coding genes); 2) Antisense (enriched around the promoter or
terminator ends of the sense transcript); 3) Intronic (located in the
area of gene coding sites); 4) Divergent lncRNA (abundanted in the
vicinity of transcription start sites); 5) Pseudogenes (genes that have
no potential of coding) [4]. Divergent lncRNAs, which are
head-to-head overlap with the coding genes, account for about 20% of
all lncRNAs. Divergent lncRNAs are strongly tied to essential growth and
developmental regulatory genes. Their functions are associated with
those of their neighboring coding genes, which can regulate those genes
in cis and encourage the diversification of higher eukaryotic
phenotypes[5]. With a countless number of lncRNA, more are
continually being found and labeled, and many lncRNAs’ roles have not
yet been thoroughly investigated.