title: Identification of tumor differentiation factor (TDF) in select CNS neurons.
abstract: Identification of central nervous system (CNS) molecules elucidates normal and pathological brain function. Tumor differentiation factor (TDF) is a recently-found protein secreted by the pituitary into the blood. TDF mRNA was detected in brain; not heart, placenta, lung, liver, skeletal muscle, or pancreas. However, TDF has an unclear function. It is not known whether TDF is expressed only by pituitary or by other brain regions. It is also not known precisely where TDF is expressed in the brain or which cells produce TDF. Database searching revealed that this molecule shares no homology with any known protein. Therefore, we investigated the distribution of TDF in the rat brain using immunohistochemistry (IHC) and immunofluorescence (IF). TDF protein was detected in pituitary and most other brain regions. Double-staining for TDF and glial fibrillary acidic protein (GFAP), an astrocyte marker, showed no co-localization. Double-staining for TDF with NeuN, a neuronal marker, showed co-localization. Not all NeuN positive cells were positive for TDF. Western blotting (WB) using NG108 neuroblastoma and GS9L astrocytoma cell lysate revealed TDF immunoreactivity in cultured neuroblastoma, not astrocytoma. These data suggest that TDF is localized in neurons, not in astrocytes. This is the first report of any cellular localization of TDF. TDF may have specific roles as a pituitary-derived hormone and in the CNS, and appears to be produced by distinct CNS neurons, not astroglia.
authors.affiliation: Biochemistry and Proteomics Group, Department of Chemistry and Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY, 13699-5810, USA.
authors.forename: Alisa G
authors.initials: AG
authors.lastname: Woods
authors.forename: Izabela
authors.initials: I
authors.lastname: Sokolowska
authors.forename: Katrin
authors.initials: K
authors.lastname: Deinhardt
authors.forename: Cristinel
authors.initials: C
authors.lastname: Sandu
authors.forename: Costel C
authors.initials: CC
authors.lastname: Darie
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats
chemical_list: D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; C000595359:tumor differentiation factor, mouse