Blog
About

16
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Control of expression of the lectin-like protein Reg-1 by gastrin: role of the Rho family GTPase RhoA and a C-rich promoter element.

      Biochemical Journal

      physiology, rhoA GTP-Binding Protein, Transcription Factors, Stomach Neoplasms, Sp3 Transcription Factor, Sp1 Transcription Factor, genetics, Sequence Deletion, Recombinant Fusion Proteins, Rats, Protein Kinase C, Promoter Regions, Genetic, Nerve Tissue Proteins, Membrane Proteins, Luciferases, Humans, Gene Expression Regulation, Gastrins, Enzyme Activation, DNA-Binding Proteins, metabolism, Cytosine, Cytokines, Binding Sites, Base Sequence, Animals

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The expression of members of the Reg family of secreted lectin-like proteins is increased in response to stress, inflammation and damage in many tissues. In the stomach, Reg is located in enterochromaffin-like cells, where its expression is stimulated by the gastric hormone gastrin. We have examined the mechanisms by which gastrin stimulates expression of Reg-1. Deletional mutations of 2.1 to 0.1 kb of the rat Reg-1 promoter in a luciferase reporter vector were transiently transfected into gastric cancer AGS-G(R) cells. All promoter fragments tested showed similar relative increases in luciferase expression in response to gastrin (1 nM). The response to gastrin of the smallest (104 bp) construct was 4.2+/-0.4-fold over basal. These responses were reduced by Ro-32-0432, a protein kinase C inhibitor, by C3-transferase, a Clostridium botulinum toxin and a selective inhibitor of the Rho family GTPase RhoA, and by co-transfection with a dominant negative form of RhoA. Co-transfection with a constitutively active form of RhoA stimulated expression 11.6+/-1.7-fold over basal. Mutations through the 104 bp construct identified a C-rich element (C-79CCCTCCC-72) required for responses to gastrin, PKC (protein kinase C) and L63RhoA (the constitutively active form of human RhoA protein containing a glutamine-to-leucine substitution at position 63). EMSAs (electrophoretic-mobility-shift assays) using nuclear extracts of control and gastrin-stimulated AGS-G(R) cells and a probe spanning -86 to -64 bp revealed multiple binding proteins. There was no effect of gastrin on the pattern of binding. Supershift assays indicated that transcription factors Sp1 and Sp3 bound the C-rich sequence. We conclude that gastrin stimulates Reg expression via activation of PKC and RhoA, that a C-rich region (-79 to -72) is critical for the response and that Sp-family transcription factors bind to this region of the promoter.

          Related collections

          Author and article information

          Journal
          15109306
          1133845
          10.1042/BJ20031793

          Comments

          Comment on this article