Complex sentence: Runx2 controls the gene expression of cyclin D2, D3, and the CDK inhibitor p21cip1 in hematopoietic cells, and it has been shown that on a molecular level, Runx associates with the cdc2 partner cyclin B1 during mitosis.
Split into simpler sentences: Runx2 controls the gene expression of cyclin D2, D3, and the CDK inhibitor p21 (cip1) in hematopoietic cells. It has been shown that on a molecular level, Runx associates with the cdc2 partner cyclin B1 during mitosis.