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  • The EMBO Journal (1997) 16, 6452 - 6465
  • doi:10.1093/emboj/16.21.6452

Phosphorylation of activation functions AF-1 and AF-2 of RARalpha and RARbig gamma is indispensable for differentiation of F9 cells upon retinoic acid and cAMP treatment

Reshma Taneja2,4, Cécile Rochette-Egly1,4, Jean-Luc Plassat1, Lucia Penna1, Marie-Pierre Gaub3 and Pierre Chambon1

  1. Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS-INSERM-ULP, Collège de France, BP 163, 67404 Illkirch-Cedex, France
  2. Present address: Department of Medicine, The Mount Sinai School of Medicine, One Gustave L.Levy Place, New York, NY 10029-6574, USA
  3. Present address: Lab. de Biochimie Biologie Moléculaire, Hôpital de Hautepierre, Avenue Molière BP 48, 67098 Strasbourg Cedex, France
  4. R.Taneja and C.Rochette-Egly are equal first authors

Correspondence to:

Pierre Chambon, E-mail: igbmc@igbmc.u-strasbg.fr

Received 16 July 1997; Revised 19 August 1997

The role of RARalpha1 and RARgamma2 AF-1 and AF-2 activation functions and of their phosphorylation was investigated during RA-induced primitive and parietal differentiation of F9 cells. We found that: (i) primitive endodermal differentiation requires RARgamma2, whereas parietal endodermal differentiation requires both RARgamma2 and RARalpha1, and in all cases AF-1 and AF-2 must synergize; (ii) primitive endodermal differentiation requires the proline-directed kinase site of RARgamma2–AF-1, whereas parietal endodermal differentiation additionally requires that of RARalpha1–AF-1; (iii) the cAMP-induced parietal endodermal differentiation also requires the protein kinase A site of RARalpha–AF-2, but not that of RARgamma; and (iv) the AF-1–AF-2 synergism and AF-1 phosphorylation site requirements for RA-responsive gene induction are promoter context-dependent. Thus, AF-1 and AF-2 of distinct RARs exert specific cellular and molecular functions in a cell-autonomous system mimicking physiological situations, and their phosphorylation by kinases belonging to two main signalling pathways is required to enable RARs to transduce the RA signal during F9 cell differentiation.

  • Keywords:

    • parietal endoderm,
    • primitive endoderm,
    • proline-directed kinases,
    • protein kinase A,
    • signal transduction