Structure and chromosomal localization of the human gene of the phosphotyrosyl phosphatase activator (PTPA) of protein phosphatase 2A.
The PTPA gene encodes a specific phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase 2A. PTPA, cloned from human genomic libraries, is encoded by one single-copy gene, composed of 10 exons and 9 introns with a total length of about 60 kb. The transcription start site was determined, and the 5' flanking sequence was analyzed for its potential as a promotor. This region lacks a TATA sequence in the appropriate position relative to the transcription start, is very GC-rich, and contains upstream of the transcription start four Sp1 sites, a feature common to many TATA-less promotors. Based on the homology with DNA binding consensus sequences of transcription factors, we identified in this promotor region several putative DNA binding sites for transcription factors, such as NF-kappa B, Myb, Ets-1, Myc, and ATF. Transfection experiments with a construct containing the PTPA promotor region inserted 5' of a luciferase reporter gene revealed that the 5' flanking sequence of the PTPA gene indeed displayed promotor activity that seems to be cell-line dependent. By fluorescence in situ hybridization and G-banding, the PTPA gene was localized to the 9q34 region. The PTPA gene is positioned centromeric of c-abl in a region embracing several genes implicated in oncogenesis.
Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, Belgium.
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C
Van Hoof
M S
MS
Aly
A
A
Garcia
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Cayla
J J
JJ
Cassiman
W
W
Merlevede
J
J
Goris
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002874:Chromosome Mapping; D002899:Chromosomes, Human, Pair 9; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004789:Enzyme Activation / Q000235:genetics; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D011401:Promoter Regions, Genetic; D054648:Protein Phosphatase 2; D011506:Proteins / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
D011506:Proteins; D014157:Transcription Factors; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; C087440:PTPA protein, human