The apolipoprotein A-I gene is actively expressed in the rapidly myelinating avian peripheral nerve.
Open Access
- 31 August 1989
- journal article
- research article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 109 (3), 1245-1256
- https://doi.org/10.1083/jcb.109.3.1245
Abstract
The expression of the apolipoprotein A-I (apo A-I) gene was investigated in the myelinating sciatic nerve. Hybridization analysis with an apo A-I cDNA probe obtained from a cDNA library of mRNA isolated from rapidly myelinating chick sciatic nerve indicated that apo A-I coding transcripts increase during development in the chick sciatic nerve in parallel with the increase of myelin lamellae. Substantial apo A-I-like immunoreactivity in chick sciatic nerve homogenates was detected by Western blotting. The amount of antigen increased from the 15-d embryonic stage of 1 d posthatch and then decreased. Two subcellular fractions corresponding to the cytoplasmic compartments were particularly enriched in apo A-I. apo A-I immunoreactivity was also found in highly purified myelin preparations. Immunohistochemical staining provided further evidence for the presence of apo A-I in the endoneurial compartment of the sciatic nerve. Electron microscopic examination of these fractions after negative staining showed the presence of spherical and disc-shaped particles resembling high density lipoproteins. The presence of apo A-I, cholesterol esters, phospholipids, and triacylglycerols in ultracentrifugal fractions corresponding to serum lipoproteins and the behavior of apo A-I on nondenaturing gradient gels implied that apo A-I was associated with lipid. Studies with short-term organ cultures of sciatic nerves from 1-d chicks strengthened the evidence for local synthesis and secretion of apo A-I and apo A-I-containing lipoproteins by this tissue. Tese results establish that the apo A-I gene is actively expressed in developing sciatic nerve during the period of rapid myelination. These findings support the hypothesis that apo A-I synthesized within the nerve participates in the local transport of lipids used in myelin biosynthesis.This publication has 47 references indexed in Scilit:
- The PO Protein of Chick Sciatic Nerve Myelin: Purification and Partial CharacterizationJournal of Neurochemistry, 1982
- A chicken histone H3 gene contains intervening sequencesNature, 1982
- Studies on Cultured Schwann Cells: The Induction of Myelin Synthesis, and the Control of Their Proliferation by A New Growth FactorJournal of Experimental Biology, 1981
- Interactions Between Axons and their Sheath CellsAnnual Review of Neuroscience, 1981
- Biosynthesis of apolipoprotein B in rooster kidney, intestine, and liver.Journal of Biological Chemistry, 1980
- Apolipoprotein B of avian very low density lipoprotein: characteristics of its regulation in nonstimulated and estrogen-stimulated roosterBiochemistry, 1980
- DEVELOPMENTAL CHANGES OF MYELIN PROTEINS IN THE CHICK PERIPHERAL NERVEJournal of Neurochemistry, 1979
- Protein Heterogeneity in Rat CNS Myelin SubfractionsPublished by Springer Nature ,1978
- Movements in the Myelin Schwann Sheath of the Vertebrate AxonNature, 1969
- In Vivo Studies of Myelinated Nerve FibersInternational Review of Cytology, 1964