Richard A. Ashmun

Learn More
The INK4a tumor suppressor locus encodes p16INK4a, an inhibitor of cyclin D-dependent kinases, and p19ARF, an alternative reading frame protein that also blocks cell proliferation. Surprisingly, mice lacking p19ARF but expressing functional p16INK4a develop tumors early in life. Their embryo fibroblasts (MEFs) do not senesce and are transformed by oncogenic(More)
The INK4a (MTS1, CDKN2) gene encodes an inhibitor (p16INK4a) of the cyclin D-dependent kinases CDK4 and CDK6 that blocks them from phosphorylating the retinoblastoma protein (pRB) and prevents exit from the G1 phase of the cell cycle. Deletions and mutations involving INK4a occur frequently in cancers, implying that p16INK4a, like pRB, suppresses tumor(More)
Mammalian D-type cyclins are growth factor-regulated, delayed early response genes that are presumed to control progression through the G1 phase of the cell cycle by governing the activity of cyclin-dependent kinases (cdks). Overexpression of mouse cyclin D1 in serum-stimulated mouse NIH-3T3 and rat-2 fibroblasts increased their rates of G0 to S- and G1- to(More)
Phage that display a surface peptide with the NGR sequence motif home selectively to tumor vasculature in vivo. A drug coupled to an NGR peptide has more potent antitumor effects than the free drug [W. Arap et al., Science (Washington DC), 279: 377-380, 1998]. We show here that the receptor for the NGR peptides in tumor vasculature is aminopeptidase N (APN;(More)
To determine the primary structure of CD13, a 150-kD cell surface glycoprotein originally identified on subsets of normal and malignant human myeloid cells, we isolated the complete sequences encoding the polypeptide in overlapping complementary DNA (cDNA) clones. The authenticity of our cDNA clones was demonstrated by the ability of the coding sequences,(More)
Three mouse cyclin-like (CYL) genes were isolated, two of which are regulated by colony-stimulating factor 1 (CSF-1) during the G1 phase of the macrophage cell cycle. CSF-1 deprivation during G1 leads to rapid degradation of CYL proteins (p36CYL) and correlates with failure to initiate DNA synthesis. However, after entering S phase, macrophages no longer(More)
Human coronaviruses (HCV) in two serogroups represented by HCV-229E and HCV-OC43 are an important cause of upper respiratory tract infections. Here we report that human aminopeptidase N, a cell-surface metalloprotease on intestinal, lung and kidney epithelial cells, is a receptor for human coronavirus strain HCV-229E, but not for HCV-OC43. A monoclonal(More)
The transcriptional mechanisms that drive colony-forming unit granulocyte-macrophage (CFU-GM) myeloid progenitors to differentiate into cells of either the granulocytic or monocytic lineage are not fully understood. We have shown that the c-Maf and c-Myb transcription factors physically interact in myeloid cells to form inhibitory complexes that hinder(More)
Cyclin D-dependent kinases act as mitogen-responsive, rate-limiting controllers of G1 phase progression in mammalian cells. Two novel members of the mouse INK4 gene family, p19 and p18, that specifically inhibit the kinase activities of CDK4 and CDK6, but do not affect those of cyclin E-CDK2, cyclin A-CDK2, or cyclin B-CDC2, were isolated. Like the(More)
Progression through the G1 phase of the cell cycle is regulated in part by the D-type cyclin-dependent kinases, cdk4 and cdk6. Genes encoding two specific inhibitors of these kinases, human p16(INK4a/MTS1) and p15(INK4b/MTS2), map to a region of common cytogenetic abnormalities on chromosome 9p21. The murine cognates of these genes were isolated and(More)