Long Laboratory Homepage

Welcome to the homepage of the laboratory of Michael W. Long, Ph.D., a part of the Department of Pediatrics, University of Michigan.

Using megakaryocyte endomitosis as a model, one group within the Long Lab is exploring the mechanisms of cell cycle control. Specifically, we hypothesize that the formation of a polyploid nucleus in megakaryocytes requires the abrogation of mitosis in order to yeild a uni-nucleate polyploid cell. We have previously shown that polyploid cells undergo two novel alterations in the mitosis-initiating cdk1/cyclin B1 protein kinase complex: a marked reduction in cdk1 (cdc2) protein levels, and elevation of cyclin B levels. Efforts are under way in the lab to further characterize cyclin B1 and identify interacting proteins, with a goal of elucidating the mechanism of endomitosis in human megakaryocytes.

Efforts in this lab have produced a serum free culture system, which allows us to culture purified populations of bone precursor cells in vitro. One aspect of this project is the investigation of the bone preosteoblast's requirement for an as yet unidentified bone accessory cell. Such an accessory cell has been shown to express soluble factor(s), which, in addition to exogenous TGF-b, are required for bone progenitor cell mitosis and differentiation. Other aspects of bone cell biology under investigation are the deposition of bone like material in vitro, and the growth of primary bone cells in simulated microgravity conditions.

• Michael W. Long, Ph.D., Primary Investigator
• Elizabeth Ashcraft, Research Associate
• Jerry Caldwell, Ph.D., Research Fellow
• Alice Curry, Ph.D., Research Fellow
• Nabanita Datta, Ph.D., Assistant Research Scientist
• Peter G. Eipers, Ph.D., Research Fellow
• Sujata Karihaloo, Ph.D., Research Fellow
• George Pipia, Doctoral Candidate
• Lynne Williams, Ph.D., Visiting Scientist

Michael W. Long, Ph.D. Department of Pediatrics, University of Michigan Room 3580, MSRB II 1150 W. Medical Center Drive Ann Arbor, MI 48109-0688