The identification of neurotrophic factor as a transferrin

Abstract

Partially purified neurotrophic factor (NTF) from chicken nerves comigrated with transferrin and a component in several preparations known to have neurotrophic effects on cultured skeletal muscle cells. One-dimensional gel electrophoretogr~s of pro&o&tic fragments of NTF and fragments obtained from transferrins purified from chicken eggs, serum and embryos were ~~stingu~hable. These purified transferrins, like NTF, all stimulated the incorporation of t3Hfthymidine and supported myotube formation to a similar degree as NTF. These studies suggest that NTF is a transferrin-like protein and that both transferrins and NTF act by initially promoting myoblast proliferation and subsequently supporting myogenesis in chick muscle cultures.~~rotro~hic factor ~yogen~~ Peptide fragment Growth factor

Transferrin gene expression visualized in oligodendrocytes of the rat brain by using in situ hybridization and immunohistochemistry.

“…Some recent data (unpublished observations) indicate that transferrin gene expression in the brain is regulated independently from its expression in the liver. While the role of transferrin in the brain is unclear, its function could be related to the general properties of transferrin as an iron binding protein (21), or it could play a more specific role such as a neurotrophic factor (5). The latter possibility is suggested by the facts that the transferrin mRNA content of the rat brain progressively increases during postnatal brain development (7) and that brain capillaries are the only blood vessels in the body that have receptors for transferrin (22).…”

“…Interest in the study of transferrin has recently increased because of its profound effect in stimulating the proliferation and differentiation of many cell populations (2,3) and because of its possible involvement as a neurotrophic factor (4,5). There are several lines of evidence which suggest that transferrin can be produced in tissues other than the liver (6,7).…”

Partial purification and characterization of the calcium-dependent and phospholipid-dependent protein kinase C from chick oviduct

“…The transferrin receptor is present in large amounts on the surface of rapidly growing cells [30] and it is phosphorylated in response to TPA treatment, possibly by Ca,PL-PK [5]. Recently, it was reported that the chicken transferrins, including a lately discovered neurotransferrin, promote proliferative activity in chick muscle cells in vitro [31]. Furthermore, neurotransferrin was found to be a mitogen for these cells 1321.…”

Partial purification and characterization of an endothelial cell growth regulator from the bovine ovary

“…Fisch & Gifford (1983) have shown that native, non-reduced TNFa elutes from Sephacryl S-200 at a molecular weight of about 48 000. The extraction procedures utilized were a modification of those used by Gospodarowicz et al (1985), Folkman et al (1984) and Beach et al (1983) for the extraction of endothelial cell growth regulators. TNFa has also been extracted from rabbit serum (Matthews, 1978;Matthews & Watkins, 1978) and E. coli cell lysates (Bringman & Aggarwal, 1987) with ammonium sulphate precipitation.…”