Analysis of the Bruton's tyrosine kinase gene promoter reveals critical PU.1 and SP1 sites.
The gene defective in X-linked agammaglobulinemia (XLA) encodes a novel protein kinase termed Bruton's tyrosine kinase (Btk). Whereas the XLA phenotype is confined to abnormalities of B-cell development and function, Btk is expressed not only in B-lymphocyte lineage but also in myeloid lineage cells. The first 450 basepairs of the Btk promoter fused to a luciferase gene displayed a similar cell-type specificity. Critical binding sites for the transcription factors PU.1 and Sp1 were identified in the proximal portion of the Btk promoter upstream of a cluster of transcriptional start sites. Mutation of either the PU.1 or Sp1 site markedly reduced the activity of a Btk promoter-luciferase reporter construct in transfection experiments. In addition, PU.1 directly transactivated the Btk promoter, and deletion of the PU.1 binding site abolished this effect. This study implicates PU.1 and Sp1 as major regulators of Btk expression and provides a foundation for further study of the regulation of this gene in XLA patients that lack Btk mRNA.
Himmelmann
A
A
Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1876, USA.
Thevenin
C
C
Harrison
K
K
Kehrl
J H
JH
D000077329:Agammaglobulinaemia Tyrosine Kinase; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002461:Cell Line, Transformed; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004790:Enzyme Induction; D015973:Gene Expression Regulation, Leukemic; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D007938:Leukemia / Q000473:pathology; D016393:Lymphoma, B-Cell / Q000473:pathology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics*; D010954:Plasmacytoma / Q000473:pathology; D011401:Promoter Regions, Genetic; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015682:Retroviridae Proteins, Oncogenic; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D011993:Recombinant Fusion Proteins; D015682:Retroviridae Proteins, Oncogenic; D016329:Sp1 Transcription Factor; C062022:v-Spi-1 protein, Friend spleen focus-forming virus; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human