Transforming growth factor-alpha in the mammalian brain. Immunohistochemical detection in neurons and characterization of its mRNA.
In this communication, we demonstrate that adult mammalian brain neurons express transforming growth factor-alpha (TGF-alpha). We used the anti-TGF-alpha monoclonal antibody, MF9, to immunohistochemically localize TGF-alpha in human and rat brain. We found specific immunoreactivity in neurons throughout the brain which was not a result of cross-reactivity of MF9 with the neuropeptide, synenkephalin. Northern blot analysis of bovine and rat brain RNA using human and rat TGF-alpha cDNA probes, respectively, revealed a single 4.8-kilobase pair mRNA with approximately equal abundance in the bovine brainstem, cerebellum, hypothalamus, and cerebral cortex. Fetal rat brain had about 2-fold more TGF-alpha mRNA than did adult rat. The brain TGF-alpha cDNA was cloned from a human neonatal brainstem library. Four identical clones were isolated after screening 10(6) recombinant lambda gt11 phage. The sequence of the 894-base pair cDNA was virtually identical with the cDNA isolated from a human renal cell carcinoma. A single alanine codon was deleted in the brain cDNA at an exon-exon junction. The alanine deletion is within the amino-terminal region of the TGF-alpha precursor that is thought to be removed by proteolytic processing of the precursor to the mature growth factor. These studies indicate that the normal mammalian brain neurons express TGF-alpha.
Kudlow
J E
JE
Department of Clinical Biochemistry, University of Toronto, Banting and Best Diabetes Centre, Ontario, Canada.
Leung
A W
AW
Kobrin
M S
MS
Paterson
A J
AJ
Asa
S L
SL
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D004745:Enkephalins / Q000378:metabolism; D007124:Immunoenzyme Techniques; D009474:Neurons / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015291:Transforming Growth Factors / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; D015291:Transforming Growth Factors; C036693:synenkephalin