Cultured embryonic chick skeletal muscle cells contain specific receptors for a myotrophic factor identified as neutrotransferrin

Thesis/Dissertation · Mon Dec 31 23:00:00 EST 1984

OSTI ID:5007330

Stamotos, C G

Cultured embryonic chick myotubes require iron during proliferation and differentiation. Ovotransferrin (OvoTF), the iron-binding protein of egg white, produced a concentration-dependent stimulation of myogenesis, as evaluated by a sensitive quantitative bioassay for acetylcholine receptors. Neurotransferrin, a myotrophic protein isolated from adult chicken sciatic nerve, is immunologically and physiologically very similar, if not identical, to OvoTf. Cultured embryonic chick spinal cord neurons were metabolically labeled with /sup 35/S-methionine, homogenized and subjected to immunoprecipitation with antibody against neurotransferrin. The authors demonstrated that neuronal cell enriched cultures synthesize and secrete neurotransferrin. The binding of OvoTf to cultured myotubes is specific, saturated at a concentration of 80 nM OvoTf and reversible. Binding of OvoTf to cultured myotubes occurs at 4/sup 0/C and at 37/sup 0/C. Internalization studies using /sup 125/I-ovotransferrin or /sup 55/Fe-OvoTf suggested that OvoTf is internalized, depleted of iron and then recycled intact to the extracellular milieu. Autoradiography of muscle cell cultures incubated with /sup 125/I-OvoTf revealed clusters of OvoTf receptors along the surface of the myotubes. Electron microscopy autoradiography of myotubes incubated with /sup 55/Fe-OvoTf showed that iron delivered by OvoTf is rapidly distributed throughout the cell. The results of the studies suggest that neurotransferrin may play a critical role during in vivo embryonic chick skeletal muscle development.

• Research Organization: Boston Univ., MA (USA)
• OSTI ID: 5007330
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
ANIMAL CELLS
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIRDS
CARBOXYLIC ACIDS
CHICKENS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON MICROSCOPY
EMBRYONIC CELLS
EVEN-ODD NUCLEI
FOWL
GLOBULINS
GLOBULINS-BETA
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
IRON 55
IRON ISOTOPES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MEMBRANE PROTEINS
METALLOPROTEINS
METHIONINE
MICROSCOPY
MUSCLES
NUCLEI
ODD-EVEN NUCLEI
ONTOGENESIS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PROTEINS
RADIOASSAY
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SULFUR 35
SULFUR ISOTOPES
TEMPERATURE DEPENDENCE
TRANSFERRIN
VERTEBRATES
YEARS LIVING RADIOISOTOPES