Cell-cycle dependent anti-FGF-2 staining of chicken cardiac myocytes: movement from chromosomal to cleavage furrow- and midbody-associated sites.
Fibroblast growth factor-2 (FGF-2) promotes cardiac myocyte proliferation and has been detected in extracellular as well as cytoplasmic and nuclear compartments. As a first step in examining the participation of intracellular FGF-2 in cardiac myocyte cell cycle we have investigated its localization in proliferative chicken cells during interphase and the various stages of mitosis in culture. We have used a previously characterized and affinity-purified anti-FGF-2 antibody preparation which recognizes the 19-22 kDa variants of chick FGF-2. By immunofluorescence, bright, punctate anti-FGF-2 labelling was observed in 26% of interphase nuclei from myocytes derived from 5 day embryonic heart ventricles; these nuclei were positive for anti-bromodeoxyuridine staining indicating that they are at the S- or G2 phase of the cell cycle. In prophase and metaphase, bright anti-FGF-2 staining was detected in apparent association with chromosomes. During anaphase, however, anti-FGF-2 staining dissociated from chromosomal locations distinctly remaining in strand-like structures in the area of ensuing cleavage furrow formation. In late telophase and cytokinesis, strong staining persisted in the area of the midbody and reappeared in a small fraction of newly formed daughter nuclei. Absorption of the antibody preparation with immobilized FGF-2 eliminated all staining. This dynamic pattern of anti-FGF-2 staining suggests that chick FGF-2 or immunologically related protein(s) not only increase in DNA-synthesizing nuclei but they may play a role in subsequent stages of mitosis and cytokinesis.
Liu
L
L
Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Winnipeg, Manitoba, Canada.
Dai
J
J
Fandrich
R R
RR
Kardami
E
E
D000818:Animals; D000906:Antibodies; D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division; D002645:Chickens; D016222:Fibroblast Growth Factor 2 / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006352:Heart Ventricles / Q000166:cytology; D007074:Immunoglobulin G; D008540:Meiosis / Q000502:physiology; D008938:Mitosis / Q000502:physiology; D009206:Myocardium / Q000166:cytology*; D016276:Ventricular Function
D000906:Antibodies; D007074:Immunoglobulin G; D016222:Fibroblast Growth Factor 2