Although recent evidence suggests that overlapping sense/antisense transcription is a common feature in higher eukaryotes, the possibility that overlapping transcripts could interact to each other and bear a specific biological function has not been explored. Here we show that a plethora of sense/antisense transcript pairs are co-expressed from 8q24.21 within the same cell and acquire a stable double-stranded RNA conformation. Interestingly, these molecules display predominantly nuclear localization and establish specific interactions with nuclear components. A detailed characterization of a particular sense/antisense pair (ndsRNA-2a) revealed that this molecule displays differential localization throughout the cell cycle, interacts with RCC1 and RAN and through the latter with the mitotic RANGAP1-SUMO1/RANBP2 complex. Notably, an increased number of bi/multi-nucleated cells and chromatin bridges were observed upon ndsRNA-2a overexpression, whereas strand-specific ndsRNA-2a knockdown leads to mitotic catastrophe and cell death. This suggests a functional role of ndsRNA-2a in cell cycle progression that critically requires its double stranded nature. Finally, the identification of hundreds of sense/antisense transcripts pairs harboring ndsRNA profile signatures and their regulation by cellular cues suggests that ndsRNAs constitute a novel class of regulatory molecules that are likely to be involved in a plethora of biological processes. Overall design: PLB985 long (3x datasets) and small (3x datasets) strand specific RNA-Seq for captured RNAs. Global PLB985 for long (2x datasets) and small RNAs (2x datasets). Global libraries for EtOH (vehicle) treated (1x dataset) or retinoic acid induced differentiated PLB985 cells (1x dataset).