| Long non-coding RNA (lncRNA) is in general considered as non-protein coding transcript with more than 200 bp in length. This limitation is due to practical considerations including the separation of RNAs in common experimental protocols. Large scale sequencing of cDNA libraries and more recently transcriptomic sequencing by next generation sequencing indicate that the number of lncRNAs is over than ten thousand in human genome. The functions of lncRNA are showed in Figure 1. In briefly, lncRNA transcribed from an upstream non-coding promoter can negative (1) or positively (2) affect expression of the downstream gene by inhibiting RNA polymerase II recruitment and/or inducing chromatin remodelling, respectively. lncRNA is able to hybridize to the pre-mRNA and block recognition of the splice sites by the spliceosome, thus resulting in an alternatively spliced transcript (3). Alternatively, hybridization of sense and antisense transcripts can allow Dicer to generate endo-siRNAs (4). The binding of lncRNA to miRNA results in the miRNA silencing (5). The complex of lncRNA and specific protein partners can modulate the protein activity (6), structure (7), localization (8) or epigenetic regulation (9). Finally, lncRNA also can produce sRNAs (10).flncRNAdb is a resource of exploring the functions of human lncRNAs which with length more than 200bp. This site with four major differentiating features is distinct from public databases. First, we identify the lncRNAs and provide the expression profiles for lncRNAs and their homologous protein-coding genes. Second, we provide the miRNA regulators of lncRNAs as well as their homologous genes. Third, we detect the lncRNA-derived endogenous siRNAs (esiRNAs) as supported by any amount of sRNA deep sequencing data and construct the interactions of lncRNA-derived esiRNAs as well as their interacting gene targets in the human genome. Finally, we present the neighboring genes between lncRNAs. |
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