title: Involvement of Fyn tyrosine kinase in progression of cytokinesis of B lymphocyte progenitor.
abstract: We analyzed the role of Fyn tyrosine kinase in cell cycle progression of B lymphocyte progenitor (pro B cell). Whereas there were no substantial defects in the intramarrow B cell genesis in the fyn(-) mouse, and long-term proliferation of fyn(-) pro B cells was maintained in vitro under a serum containing culture condition, the cell cycle was arrested at G2/M upon serum deprivation. Morphological analyses demonstrated that the cytokinesis of fyn(-) pro B cells was retarded in the presence of serum and that the entry of fyn(-) pro B cells into late telophase was completely blocked under the serum-free condition. In contrast, the earlier phases of mitosis of fyn(-) pro B cells proceeded normally without FCS. This failure to initiate late telophase resulted in the accumulation of elliptical binucleated cells that might be the outcome of the nuclear division without cytokinesis. Consistent with this defect in the progression of cytokinesis, Fyn was localized in the midspace of dividing pro B cells at anaphase. These results suggested that Fyn localizes at the midspace of dividing pro B cells and regulates the progression of cytokinesis.
authors.affiliation: Department of Molecular Genetics, Faculty of Medicine, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yasunaga
authors.forename: T
authors.initials: T
authors.lastname: Yagi
authors.forename: N
authors.initials: N
authors.lastname: Hanzawa
authors.forename: M
authors.initials: M
authors.lastname: Yasuda
authors.forename: Y
authors.initials: Y
authors.lastname: Yamanashi
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Aizawa
authors.forename: Y
authors.initials: Y
authors.lastname: Miyauchi
authors.forename: S
authors.initials: S
authors.lastname: Nishikawa
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D015153:Blotting, Western; D001853:Bone Marrow / Q000502:physiology; D001854:Bone Marrow Cells; D002451:Cell Compartmentation; D002455:Cell Division / Q000502:physiology; D016895:Culture Media, Serum-Free; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006651:Histocytochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008938:Mitosis / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051076:Proto-Oncogene Proteins c-fyn
chemical_list: D016895:Culture Media, Serum-Free; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn