Unique features enable lncRNA-mediated control of cell fate and function. (A) lncRNAs can bind nucleic acids via base-pairing or proteins through secondary structures. The same lncRNA can harbor multiple interaction modules, enabling it to spatially organize diverse effectors and their targets and to scaffold ribonucleoprotein complexes. (B) lncRNAs are highly tissue-, developmental-, and physiological state-specific. Shown are 2 loci encoding lncRNAs (purple and blue boxes); gray boxes encode other transcripts. During early development (left), 1 lncRNA (purple transcripts) can form distinct nuclear compartments by recruiting a regulatory protein (yellow circles) to genomic sites surrounding its own locus. That lncRNA may be turned off at a later developmental stage whereas a second (blue transcript) is induced and recruits the same yellow protein but to different chromosome loci. (C) lncRNA–protein complexes are dynamic and flexible. The same lncRNA can bind distinct proteins based on their local concentration or by adopting distinct structural conformations with distinct RNA–protein binding affinities.