title: Mapping of CIP/KIP inhibitors, G1 cyclins D1, D3, E and p53 proteins in the rat term placenta.
abstract: As cell cycle regulation is fundamental to the normal growth and development of the placenta, the aim of the present study was to determine the immunolocalizations of cell cycle related proteins, which have key roles in proliferation, differentiation and apoptosis during the development of the rat placenta. Here immunohistochemistry has been used to localize G1 cyclins (D1, D3, E), which are major determinants of proliferation, CIP/KIP inhibitors (p21, p27, p57), p53 as a master regulator and proliferating cell nuclear antigen in all cell types of the rat term placenta. The proportion of each cell type immunolabeled was counted. Cyclin D1 and cyclin D3 were present mostly in cells of the fetal aspect of the placenta, whereas the G1/S cyclin E was present only in the spongio- and labyrinthine trophoblast populations. Among the CIP/KIP inhibitors, p21 was present only in cells of the fetal aspect whereas p27 and p57 were found in all cell types studied. p53 was only found in a small proportion of cells with no co-localization of p53 and p21. The data suggest that the cells of the fetal side of the rat placenta still have some proliferation potential which is kept in check by expression of the CIP/KIP cell cycle inhibitors, whereas cells of the maternal aspect have lost this potential. Apoptosis is only marginal in the term rat placenta. In conclusion, proliferation and apoptosis in rat placental cells appears controlled mostly by the CIP/KIP inhibitors in late pregnancy.
authors.affiliation: Department of Histology and Embryology, Antalya, Turkey. korgun@akdeniz.edu.tr
authors.forename: Emin Turkay
authors.initials: ET
authors.lastname: Korgun
authors.forename: Gozde
authors.initials: G
authors.lastname: Unek
authors.forename: Emilio
authors.initials: E
authors.lastname: Herrera
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Jones
authors.forename: Christian
authors.initials: C
authors.lastname: Wadsack
authors.forename: Dijle
authors.initials: D
authors.lastname: Kipmen-Korgun
authors.forename: Gernot
authors.initials: G
authors.lastname: Desoye
mesh_terms: D000818:Animals; D017209:Apoptosis; D049109:Cell Proliferation; D019938:Cyclin D1 / Q000378:metabolism*; D056743:Cyclin D3 / Q000378:metabolism*; D019927:Cyclin E / Q000378:metabolism*; D056766:Cyclin G1 / Q000378:metabolism*; D050756:Cyclin-Dependent Kinase Inhibitor Proteins / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005260:Female; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014327:Trophoblasts / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: C530106:Ccnd1 protein, rat; C534698:Ccnd3 protein, rat; C534704:Ccng1 protein, rat; D056743:Cyclin D3; D019927:Cyclin E; D056766:Cyclin G1; D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1