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A Radioimmunoassay for Ependymins β and γ: Two Goldfish Brain Proteins Involved in Behavioral Plasticity
Author(s) -
Schmidt Rupert,
Shashoua Victor E
Publication year - 1981
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1981.tb00574.x
Subject(s) - radioimmunoassay , glycoprotein , antigenicity , antigen , antiserum , antibody , biology , cerebrospinal fluid , beta (programming language) , extracellular , biochemistry , chemistry , microbiology and biotechnology , immunology , neuroscience , computer science , programming language
A radioimmunoassay (RIA) using 125 I‐labeled antigen was developed for the quantitative determination of two goldfish brain proteins (ependymins β and γ). The proteins were isolated from the cerebrospinal fluid (CSF) and cells of the ependymal zone surrounding goldfish brain ventricles. The turnover rates of β and γ were previously shown to be specifically enhanced after the animals successfully acquired a new pattern of swimming behavior. Femtomole quantities of ependymin β were measurable by the RIA. In applications of the assay, β and γ ependymins were found to have common immunological properties, since 125 I‐β‐antigen bound to antibody could be displaced by unlabeled ependymin γ as well as ependymin β but not by a variety of other proteins including several purified glycoproteins isolated from goldfish brain. The ependymins were shown to constitute 14% of the total protein content of the brain extracellular fluid and also to be present as a minor component of the serum proteins (0.3%). Ependymins β and γ have an immunological reactivity in these fractions that can be increased by a factor of 30 on heating. The data suggest that the antigenicity of the molecules is highly masked, and that it may require some unraveling of the quaternary structure of the proteins before maximal interaction with the antisera becomes possible.