Accepted_test

Mitosis is a highly complex process involving numerous tightly regulated genes and their protein products. Previous studies have revealed the lncRNA composition of mitotic chromosomes, indicating potential functional significance of these RNAs. Small RNAs, best known for RNA interference, could also play important roles in mitosis. However, to data, the profile of chromosome-associated small RNA has yet been systematically investigated in mammals. In this study, we performed deep sequencing of chromosome-associated small RNAs in metaphase of mouse 3T3 cell line under three different conditions – no salt, low salt and high salt. The identified small RNAs with high abundance are highly consistent among the three conditions, indicating the functional significance of these stably attached RNAs. Most of these small RNAs can be mapped to existing features such as microRNAs and Piwi-interacting RNAs, while a considerable amount (36.3%) could not be annotated. In addition, some unannotated small RNAs are not present in the interphase 3T3 cell line, suggesting their special function for mitosis.