Calbindin-D28k, calretinin, and recoverin immunoreactivities in developing chick pineal gland.
Calbindin-D28k, calretinin, and recoverin, three intracellular calcium-binding proteins belonging to the troponin C/calmodulin superfamily, were immunohistochemically localized in chick pineal during development [from embryonic day 16 (E16) to postnatal day 14 (P14)]. At E18, only calretinin immunoreactivity could be detected in nuclei from follicular pinealocytes. With development, calretinin immunoreactivity expanded from nucleus to cytoplasm, and calretinin immuno-positive cell number increased. At P14 almost al pinealocytes were calretinin positive. Calbindin-D28k immunoreactivity was not detected before E20. During development, many follicular and parafollicular pinealocytes became strongly calbindin-D28k positive, reaching a peak both in intensity and in number at P7; thereafter their number decreased. In addition to pinealocytes, neuron-like cells appeared calbindin-D28k positive at E20 and calretinin positive at P7. Recoverin, a myristoylated protein isolated from vertebrate photoreceptor and which might participate in the inactivation of the phototransduction cascade, was transiently expressed in follicular and parafollicular pinealocytes from P1 to P14 with a maximal expression at P7. This transitory expression may coincide with a transitory light sensitivity period in chick pinealocytes, before complete maturity of the pineal gland.
Bastianelli
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Laboratoire d'Histologie, Faculté de Médecine, Université Libre de Bruxelles, Brussels, Belgium.
Pochet
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D000818:Animals; D000951:Antigens, Neoplasm / Q000032:analysis; D064032:Calbindin 2; D064026:Calbindins; D002135:Calcium-Binding Proteins / Q000032:analysis*; D002642:Chick Embryo; D002645:Chickens; D005136:Eye Proteins / Q000032:analysis; D051597:Hippocalcin; D007124:Immunoenzyme Techniques; D008074:Lipoproteins; D009419:Nerve Tissue Proteins / Q000032:analysis; D010870:Pineal Gland / Q000737:chemistry* / Q000196:embryology / Q000254:growth & development; D051603:Recoverin; D064030:S100 Calcium Binding Protein G / Q000032:analysis*
D000951:Antigens, Neoplasm; D064032:Calbindin 2; D064026:Calbindins; D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D064030:S100 Calcium Binding Protein G; D051603:Recoverin; D051597:Hippocalcin