Expression of Bruton's agammaglobulinemia tyrosine kinase gene, BTK, is selectively down-regulated in T lymphocytes and plasma cells

Smith, C.I. et al. (1994) Expression of Bruton's agammaglobulinemia tyrosine kinase gene, BTK, is selectively down-regulated in T lymphocytes and plasma cells. Journal of Immunology, 152(2), pp. 557-65. (PMID:8283037)

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The gene mutated in the human disease, X-linked agammaglobulinemia (XLA), is related to the Src gene family of cytoplasmic protein-tyrosine kinases and is designated Btk (Bruton's agammaglobulinemia tyrosine kinase; formerly Atk/Bpk; the human gene is denoted BTK, using capital letters according to the kinase nomenclature). We have recently reported that this gene is expressed in B lymphocytes and that the specific mRNA was undetectable in T cells using Northern blotting. Further analyses of different sources of B and T lymphocytes confirmed this pattern. However, BTK transcripts were undetectable in four plasmacytoma lines. Moreover, as virtually normal amounts of BTK transcripts were found in PBMC from two patients carrying a point mutation in BTK, despite low B cell numbers, we anticipated that the gene would also be expressed in cells of other lineages. The erythroleukemia cell line K-562, the promyelocytic line HL-60 and the histiocytic lymphoma line U-937 were found to have BTK mRNA levels comparable to B cells. BTK mRNA was also detected in monocytes from healthy donors as well as in the human immature basophilic cell line KU812, in the human mast cell leukemia cell line HMC-1 and in the CD34 expressing myeloblast KG-1. A similar expression pattern was obtained when BTK protein was analyzed by immunoprecipitation and Western blotting. Using a polymerase chain reaction-based analysis, a small amount (less than 1% of the level in B cells) of BTK mRNA was identified in T lymphocytes. Our findings are compatible with a general expression of the BTK gene in hematopoietic cells, except in T lymphocytes and plasma cells, in which the transcript level is selectively down-regulated.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Vetrie, Dr David
Authors: Smith, C.I., Baskin, B., Humire-Greiff, P., Zhou, J.N., Olsson, P.G., Maniar, H.S., Kjellén, P., Lambris, J.D., Christensson, B., Hammarström, L., Bentley, D., Vetrie, D., Islam, K., Vorechovsky, I., and Sideras, P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cancer Sciences
Journal Name:Journal of Immunology
ISSN (Online):1550-6606

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