Immunology ellular Cellular Immunology 235 (2005) 46–55 www.elsevier.com/locate/ycimm 0008-8749/$ - see front matter  2005 Elsevier Inc. All rights reserved. doi:10.1016/j.cellimm.2005.07.001 DiVerential expression and molecular characterisation of Lmo7, Myo1e, Sash1, and Mcoln2 genes in Btk-defective B-cells Jessica M. Lindvall a,¤,1 , K. Emelie M. Blomberg a,1 , Anders Wennborg b , C.I. Edvard Smith a,¤ a Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Hälsovägen 7, SE-141 57 Huddinge, Sweden b Department of Biosciences, Karolinska Institutet, Hälsovägen 7, SE-141 57 Huddinge, Sweden Received 24 March 2005; accepted 15 July 2005 Available online 30 August 2005 Abstract Purpose: Bruton’s tyrosine kinase is crucial for B-lymphocyte development. By the use of gene expression proWling, we have iden- tiWed four expressed sequence tags among 38 potential Btk target genes, which have now been characterised. Methods: Bioinformatics tools including data mining of additional unpublished gene expression proWles, sequence veriWcation of PCR products and qualitative RT-PCR were used. Stimulations targeting the B-cell receptor and the protein kinase C were used to activate whole B-cell splenocytes. Results: Target genes were characterised as Lim domain only 7 (Lmo7); Myosin1e (Myo1e); SAM and SH3 domain containing 1 (Sash1); and Mucolipin2 (Mcoln2). Expression was found in cell lines of diVerent origin and developmental stages as well as in whole B-cell splenocytes and Transitional type 1 (T1) splenic B-cells from wild type and Btk-defective mice, respectively. By the use of semi- quantitative RT-PCR we found Sash1 not to be expressed in the investigated haematopoietic cell lines, while transcripts were found in whole splenic B-cells from both wild type and Btk-defective mice, whereas Lmo7, Myo1e, and Mcoln2 were expressed in both B- cell lines and primary B-lymphocytes. Except for Lmo7, the transcript level was similarly aVected by stimulation in control and Btk- defective cells.  2005 Elsevier Inc. All rights reserved. Keywords: Xid; XLA; Btk; Itk; Tec; Bmx; Lmo7; Myo1e; Sash1; Mcoln2 1. Introduction An intact B-lymphocyte development is crucial for a normal immune response. Mutations in any of the genes critical for the diVerentiation of B-cells disrupt this pro- cess. One of these key molecules is encoded by the Bru- ton’s tyrosine kinase (BTK) gene, which belongs to the Tec family of cytoplasmic kinases [1–4]. Mutation in this gene causes a partial block between the pro- and pre-B- cell stage as well as a total block between the pre- and mature B-cell stage, and leads to a primary immunodeW- ciency disease called X-linked agammaglobulinemia (XLA) in humans [5,6] and X-linked immunodeWciency disease (Xid) in mice [7–9]. The phenotype in humans is more severe compared to the mouse, where only a partial block between the pre- and mature B-cell stage is estab- lished [10–13]. Since Btk is a cytoplasmic tyrosine kinase it seems likely that loss of Btk results in defective downstream signalling, aVecting various eVector molecules. For this reason we have recently proWled the gene expression pat- tern in Btk-defective whole primary splenic B-cells from Xid and Btk KO mice with the AVymetrix GeneChip * Corresponding authors. Fax: +46 8 58583656 (J.M. Lindvall). E-mail addresses: jessica.lindvall@crc.ki.se (J.M. Lindvall), edvard. smith@crc.ki.se (C.I.E. Smith). 1 These two authors contributed equally to this paper.