title: Translocation of bFGF to the nucleus is G1 phase cell cycle specific in bovine aortic endothelial cells.
abstract: Primary cultures of adult bovine aortic endothelial (ABAE) cells require bFGF to grow. G1-arrested cells, obtained after 48 h without serum and bFGF, were found to enter S phase and grow synchronously for at least two generations on addition of bFGF. In growing cells bFGF was detected both in the cytoplasm (90%) and in the nucleus (10%) where it accumulates in the nucleolus. It was not detected in the nucleus of confluent cells. bFGF uptake was continuous in the cytoplasm throughout the cell cycle with a maximum in G2, while nuclear uptake occurred only in late G1. Cytoplasmic bFGF (18.4 kd) is cleaved into a 16.5 kd peptide in G1 (t1/2 = 30 min). In the nucleus the 18.4 kd form was the only one detected 2 h following bFGF addition and was then cleaved into the 16.5 kd in early S phase. These results are consistent with the possibility that in addition to the classical pathway of signal transduction, bFGF is directly translocated to the nucleus in late G1, and could play a role in replication and/or in transcription of rDNA.
authors.affiliation: Centre de Recherche de Biochimie et de Genetique Cellulaires, CNRS, Toulouse, France.
authors.forename: V
authors.initials: V
authors.lastname: Baldin
authors.forename: A M
authors.initials: AM
authors.lastname: Roman
authors.forename: I
authors.initials: I
authors.lastname: Bosc-Bierne
authors.forename: F
authors.initials: F
authors.lastname: Amalric
authors.forename: G
authors.initials: G
authors.lastname: Bouche
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D001692:Biological Transport / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D007399:Interphase / Q000502:physiology*; D007457:Iodine Radioisotopes; D009697:Nucleolus Organizer Region / Q000378:metabolism; D013347:Subcellular Fractions / Q000032:analysis
chemical_list: D007457:Iodine Radioisotopes; D005346:Fibroblast Growth Factors