The ubiquitous presence of long noncoding RNAs (lncRNAs) in eukaryotes points to 
the importance of understanding how their sequences impact function. As many 
lncRNAs regulate nuclear events and thus must localize to nuclei, we analyzed 
the sequence requirements for nuclear localization in an intergenic lncRNA named 
BORG (BMP2-OP1-responsive gene), which is both spliced and polyadenylated but is 
strictly localized in nuclei. Subcellular localization of BORG was not dependent 
on the context or level of its expression or decay but rather depended on the 
sequence of the mature, spliced transcript. Mutational analyses indicated that 
nuclear localization of BORG was mediated through a novel RNA motif consisting 
of the pentamer sequence AGCCC with sequence restrictions at positions -8 (T or 
A) and -3 (G or C) relative to the first nucleotide of the pentamer. Mutation of 
the motif to a scrambled sequence resulted in complete loss of nuclear 
localization, while addition of even a single copy of the motif to a 
cytoplasmically localized RNA was sufficient to impart nuclear localization. 
Further, the presence of this motif in other cellular RNAs showed a direct 
correlation with nuclear localization, suggesting that the motif may act as a 
general nuclear localization signal for cellular RNAs.