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Purification of the Chick Eye Ciliary Neuronotrophic Factor
Author(s) -
Barbin Gilles,
Manthorpe Marston,
Varon Silvio
Publication year - 1984
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.1471-4159.1984.tb05410.x
Subject(s) - ciliary neurotrophic factor , ciliary ganglion , isoelectric point , biology , nerve growth factor , ciliary body , cholinergic neuron , microbiology and biotechnology , cholinergic , isoelectric focusing , endocrinology , medicine , biochemistry , chemistry , neuroscience , receptor , neurotrophic factors , enzyme
Dissociated 8‐day chick embryo ciliary ganglionic neurons will not survive for even 24 h in culture without the addition of specific supplements. One such supplement is a protein termed the ciliary neuronotrophic factor (CNTF) which is present at very high concentrations within intraocular tissues that contain the same muscle cells innervated by ciliary ganglionic neurons in vivo. We describe here the purification of chick eye CNTF by a 2½‐day procedure involving the processing of intraocular tissue extract sequentially through DE52 ion‐exchange chromatography, membrane ultrafiltration‐concentration, sucrose density gradient ultracentrifugation, and preparative sodium dodecyl sulfate‐polyacrylamide gradient electrophoresis. An aqueous extract of the tissue from 300 eyes will yield about 10–20 μg of biologically active, electrophoretically pure CNTF with a specific activity of 7.5 × 10 6 trophic units/mg protein. Purified CNTF has an M r of 20,400 daltons and an isoelectric point of about 5, as determined by analytical gel electrophoresis. In addition to supporting the survival of ciliary ganglion neurons, purified CNTF also supports the 24‐h survival of cultured neurons from certain chick and rodent sensory and sympathetic ganglia. CNTF differs from mouse submaxillary nerve growth factor (NGF) in molecular weight, isoelectric point, inability to be inactivated by antibodies to NGF, ability to support the in vitro survival of the ciliary ganglion neurons, and inability to support that of 8‐day chick embryo dorsal root ganglionic neurons. Thus, CNTF represents the first purified neuronotrophic factor which addresses parasympathetic cholinergic neurons.