Analysis of a segment of the human glial fibrillary acidic protein gene that directs astrocyte-specific transcription.
To understand astrocyte-specific transcription, we have been studying the human gfa gene. This gene encodes glial fibrillary acidic protein (GFAP), an intermediate filament protein expressed primarily in astrocytes. A survey of the gfa 5' flanking region showed it to contain several segments that contribute to expression of a chloramphenicol acetyltransferase reporter gene in transfected cells. The most active of these was the 124-bp B region, which spans bp -1612 to -1489. We have now used site-directed mutagenesis to analyze this region in greater detail, and show that the B region itself contains several important elements. The most crucial of these is a consensus AP-1 sequence, the binding site for the Fos and Jun families of transcription factors. The presence of members of both these families in the glial fibrillary acidic protein-expressing U251 cell line used for our transfection studies was verified by gel mobility-shift experiments. This is the first demonstration of the functioning of a specific transcription factor site for astrocytes, and provides a focus for future studies of glial fibrillary acidic protein regulation during development and reactive gliosis.
Laboratory of Molecular Biology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
K
K
Masood
F
F
Besnard
Y
Y
Su
M
M
Brenner
D001253:Astrocytes / Q000502:physiology*; D001483:Base Sequence; D001665:Binding Sites; D016384:Consensus Sequence; D005796:Genes; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D014158:Transcription, Genetic
D005904:Glial Fibrillary Acidic Protein; D015345:Oligonucleotide Probes; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun