interacts with and regulates cell proliferation.

Geminin is a master regulator of cell-cycle progression that ensures the timely onset of DNA replication and prevents re-replication in vertebrates and invertebrates. Previously, we identified two genes, and , in the silkworm , and we found that RNA interference of led to re-replication. However, the function of remains poorly understood. In this study, we found that knockdown of can improve cell proliferation, and upregulated G2/M-associated gene-/ expression. Then, we performed yeast two-hybrid screening to identify interacting proteins. Our results yielded 23 interacting proteins, which are involved in DNA replication, chromosome stabilization, embryonic development, energy, defense, protein processing, or structural protein. Here, we focused on BmRRS1, a chromosome congression-related protein that is closely related to cell cycle G2/M progression. The interaction between BmGeminin2 and BmRRS1 was confirmed by immunofluorescence and immunoprecipitation. Analysis of its expression profile showed that was related to . In addition, overexpression downregulated the transcript. Knockdown of led to upregulation of the transcript. Furthermore, overexpression of can upregulate G2/M-associated gene-/ expression, and improved cell proliferation, consistent with the effects of knockout. In addition, RNA interference can eliminate the impact of knockout on cell proliferation, the ratio of cell cycle stage and the expression of /. These data suggested that the cell proliferation advantage of knockout was closely related to . Our findings provide insight into the functions of and the mechanisms underlying the regulation of the cell cycle in the silkworm.