• A minimal serpin promoter with high activity in haematopoietic progenitors and activated T cells.

      Hampson, Lynne; Hampson, Ian N; Babichuk, Charolyn K; Cotter, Laura A; Bleackley, R Chris; Dexter, T Michael; Cross, Michael A; CRC Department of Hematopoietic Cell and Gene Therapeutics, Paterson Institute for Cancer Research, Wilmslow Road, Manchester M20 4BX, UK. lynne.hampson@man.ac.uk (2001)
      INTRODUCTION: The serine protease inhibitor Serpin 2A is highly expressed in ex vivo bipotent granulocyte/macrophage progenitor cells and in cultured myeloid stem cells. The gene undergoes rapid down-regulation as these cells are induced to differentiate, and constitutive expression in cultured myeloid stem cells retards maturation. Serpin 2A is also expressed in T cells as a consequence of activation. We now report analysis of the upstream regulatory elements that control Serpin 2A transcription. MATERIALS AND METHODS: Using primer extension and rapid amplification of cDNA ends the transcription start site of the Serpin 2A gene was mapped, and a 1.2 Kb genomic upstream fragment cloned and sequenced. Promoter activity and protein binding of deletion and site-directed mutant constructs were analysed by transient transfection and by electrophoretic mobility shift assays. RESULTS: A minimal promoter fragment was identified with high activity dependent on NF-kappa and Moloney murine leukaemia enhancer factor LVa binding sites in both myeloid stem cells and activated T cells. NF-kappa was shown to be the main DNA binding protein in T cells, whereas that in haematopoietic stem cells appears to be novel. CONCLUSION: Serpin 2A promoter activity in T cells is due predominantly to NF-kappa binding to its consensus site. Activity in haematopoietic stem cells appears to be mediated by a novel protein, which recognises the NF-kappa consensus only in the context of flanking sequences. This concise regulatory element may be of potential value in gene therapeutic applications.
    • Upstream elements bestow T-cell and haemopoietic progenitor-specific activity on the granzyme B promoter.

      Johnson, Barbra A; John, Victoria A; Henschler, Reinhard; Hampson, Ian N; Heyworth, Clare M; Babichuk, Charolyn K; Bleackley, R Chris; Dexter, T Michael; Cross, Michael A; Section of Haemopoietic Cell and Gene Therapeutics, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester M20 4BX, UK. (1999-06-24)
      Cytotoxic T cells and early haemopoietic progenitors share the expression of a number of specific genes. Of these, granzyme B has attracted particular interest because of its role in inducing apoptosis during cytotoxic T cell-mediated target cell killing, and its potential role in the mobilisation and homeostasis of haemopoietic stem cells. Studies of granzyme B regulation should therefore yield valuable information concerning the molecular control of these processes, and also identify elements capable of directing gene expression to two cell types of relevance to gene therapy. Here we show that proximal regulatory elements already known to direct promoter activity in T cells are similarly active in haemopoietic progenitors. However, this activity is not strictly specific, since the promoter regions also direct low levels of reporter gene expression in fibroblasts. More importantly, we also report the presence of two previously unidentified clusters of DNaseI hypersensitive sites upstream from the murine granzyme B gene, and show that these regions impart both increased transcriptional activity and the appropriate cell type specificity on the granzyme B promoter. These upstream regulatory regions are therefore likely to play a key role in the coordination of granzyme B expression in vivo.