The human histone gene expression regulator HBP/SLBP is required for histone and DNA synthesis, cell cycle progression and cell proliferation in mitotic cells.

Histone proteins are essential for chromatin formation, and histone gene expression is coupled to DNA synthesis. In metazoans, the histone RNA binding protein HBP/SLBP is involved in post-transcriptional control of histone gene expression. In vitro assays have demonstrated that human HBP/SLBP is involved in histone mRNA 3' end formation and translation. We have inhibited human HBP/SLBP expression by RNA interference to determine its function during the mitotic cell cycle. Inhibition of HBP/SLBP expression resulted in the inhibition of histone gene expression and DNA synthesis, the inhibition of cell cycle progression in S phase and the inhibition of cell proliferation. These findings indicate that human HBP/SLBP is essential for the coordinate synthesis of DNA and histone proteins and is required for progression through the cell division cycle.