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Publication Abstract from PubMed

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a highly abundant nuclear long noncoding RNA that promotes malignancy. A 3'-stem-loop structure is predicted to confer stability by engaging a downstream A-rich tract in a triple helix, similar to the expression and nuclear retention element (ENE) from the KSHV polyadenylated nuclear RNA. The 3.1-A-resolution crystal structure of the human MALAT1 ENE and A-rich tract reveals a bipartite triple helix containing stacks of five and four U*A-U triples separated by a C(+)*G-C triplet and C-G doublet, extended by two A-minor interactions. In vivo decay assays indicate that this blunt-ended triple helix, with the 3' nucleotide in a U*A-U triple, inhibits rapid nuclear RNA decay. Interruption of the triple helix by the C-G doublet induces a 'helical reset' that explains why triple-helical stacks longer than six do not occur in nature.

Structural insights into the stabilization of MALAT1 noncoding RNA by a bipartite triple helix.,Brown JA, Bulkley D, Wang J, Valenstein ML, Yario TA, Steitz TA, Steitz JA Nat Struct Mol Biol. 2014 Jul;21(7):633-40. doi: 10.1038/nsmb.2844. Epub 2014 Jun, 22. PMID:24952594^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.