Riol H, Tardy M, Rolland B, Lévesque G, Murthy M R
Department of Biochemistry, Faculty of Medicine, Laval University, Quebec, Canada.
J Neurosci Res. 1997 Apr 1;48(1):53-62.
Glial fibrillary acidic protein (GFAP), an astroglial marker, has been detected in the peripheral nervous system (PNS) in a shorter version and its mRNA in a longer form (beta-type) than the brain alpha-type. To determine the characteristics of the GFAP gene expression in nonneural cells, we have investigated its in vivo transcription and translation products in human lymphocytes. Using RT-PCR, we demonstrate that the GFAP gene is transcribed in these cells. Most or all of the mRNA resulting from this transcription was longer than the brain-type at its 5' end and thus may correspond to the beta-type. In addition, immunoblotting of lymphocyte extracts with a monoclonal antibody revealed a 41 KDa fragment instead of the 50 KDa expected from brain GFAP. These results suggest that GFAP expression in lymphocytes is preferentially of the PNS beta-type giving rise to longer mRNA and shorter protein. However, compared to two other astroglial mRNAs (S-100beta and aldolase C) which were synthesized in significant amounts in lymphocytes, GFAP mRNA was detected in minute amounts representing 0.03% of the brain level. This low expression may subserve a special role in lymphocytes since it is translated.
