Suppression of growth factor-induced CYL1 cyclin gene expression by antiproliferative agents

Abstract

A recently identified novel mammalian cyclin (CYL1), induced by growth factors and apparently functional during the GI phase of the cell cycle, is of potential significance, given that cell division is primarily controlled in G1. We have measured CYL1 gene expression in murine bone marrow-derived macrophages (BMM), a normal cell type dependent upon colony-stimulating factors (CSFs) for survival and proliferation. The induction of CYL1 mRNA levels correlated strongly with stimulation of DNA synthesis, since elevated CYL1 mRNA levels occurred in response to the mitogenic stimuli, CSF-1, and granulocyte/macrophage CSF, but not to nonmitogenic macrophage-activating agents. BMM are subject to cel..