The alpha 5 beta 1 fibronectin receptor. Characterization of the alpha 5 gene promoter.
A genomic clone containing the gene for the alpha 5 subunit of the human alpha 5 beta 1 integrin complex was isolated by screening a human genomic library with the previously described alpha 5 cDNA (Argraves, W. S., Suzuki, S., Arai, H., Thompson, K., Pierschbacher, M. D., and Ruoslahti, E. (1987) J. Cell Biol 105, 1183-1190). The alpha 5 gene 5'-flanking region lacks both TATA and CCAAT boxes, and it is located in a CpG island. This region was an active promoter in transfection assays using the HT-1080 cell line (fibrosarcoma), which expresses alpha 5, but was inactive in the Raji cell line (B cell), which does not express alpha 5. These results indicate that the alpha 5 gene 5'-flanking region acts as a promoter that exhibits the expected cell-type specificity. Deletion of alpha 5 promoter sequences from position -657 to -178 caused transcription stimulation, suggesting that a silencer is located between these sites. Successive 5' deletions from position -178 decreased promoter activity until activity was essentially eliminated on deletion to position -27. Isolation of a functional promoter for the alpha 5 gene is a first step in understanding how expression of this gene is controlled at the molecular level.
Birkenmeier
T M
TM
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
McQuillan
J J
JJ
Boedeker
E D
ED
Argraves
W S
WS
Ruoslahti
E
E
Dean
D C
DC
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D002872:Chromosome Deletion; D004247:DNA / Q000235:genetics; D005353:Fibronectins / Q000378:metabolism*; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic / Q000235:genetics*; D016385:TATA Box; D014158:Transcription, Genetic
D005353:Fibronectins; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic; D004247:DNA