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Developmental regulation of fatty acid binding protein in neural tissue
Author(s) -
Sellner Peggy
Publication year - 1994
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/aja.1002000408
Subject(s) - retina , biology , immunolabeling , microbiology and biotechnology , outer nuclear layer , inner nuclear layer , retinal , fatty acid binding protein , embryonic stem cell , ganglion cell layer , embryogenesis , ganglion , western blot , immunohistochemistry , anatomy , embryo , biochemistry , neuroscience , immunology , gene
Fatty acid binding proteins (FABP) constitute a family of small, cytosolic carriers of hydrophobic ligands. These proteins are thought to be important for lipid trafficking toward specific metabolic pathways, and are potentially important for the establishment of characteristic lipid compositions of neural tissue. In the embryonic chick retina and brain, FABP resembles the heart subtype, as determined by protein characterization and immunoblot studies. In this paper, the developmental expression and cellular localization of chick retinal FABP were examined. Results of immunoblot analysis suggest that FABP is maximally expressed around embryonic day 9 (E9) and declines thereafter. In adult retinas, FABP is barely detectable on a Western blot. Immunohistochemical staining of the retina shows light labeling on day E6 and a more intense staining throughout the retina on day E9. As the retina differentiates, labeling becomes increasingly localized. By day E18 subpopulations of ganglion cells and photoreceptor inner segments are stained, as are all photoreceptor cell bodies, most of the inner nuclear layer, and the nerve fiber layer. Staining is decreased in older retinas such that in adult animals, only light staining of the photoreceptor cell bodies is visible. The decrease in relative amount of FABP in the retina after day E9 suggests a role for FABP in the early stages of retinal differentiation. Localization in the retina is consistent with this hypothesis, as label becomes more restricted to those cells undergoing maturation at a particular developmental age. Thus, in young embryos (E6–E9), FABP immunolabeling is apparent throughout the retina, and transiently localizes at different ages (E12–E15) to plexiform and nuclear layers. Near hatching (E18–E21), the photoreceptors are in the final stages of maturation, and are the principal cells immunoreactive for FABP. In the adult retina, FABP lightly labels only the photoreceptor cells bodies; thus, we conclude that chick retinal FABP is not involved in outer segment membrane homeostasis. Instead, FABP may serve to sequester fatty acids needed for the period of neurite outgrowth which occurs as the retina ends its mitotic cycles and begins the process of synaptogenesis. © 1994 Wiley‐Liss, Inc.