TY - JOUR
T1 - Intragenic duplication: a novel mutational mechanism in hereditary pancreatitis
AU - Joergensen, Maiken T
AU - Geisz, Andrea
AU - Brusgaard, Klaus
AU - Schaffalitzky de Muckadell, Ove B.
AU - Hegyi, Péter
AU - Gerdes, Anne-Marie Axø
AU - Sahin-Tóth, Miklós
PY - 2011/5
Y1 - 2011/5
N2 - Objectives: In a hereditary pancreatitis family from Denmark, we identified a novel intragenic duplication of 9 nucleotides in exon-2 of the human cationic trypsinogen (PRSS1) gene (c.63-71dup) which at the amino-acid level resulted in the insertion of 3 amino acids within the activation peptide of cationic trypsinogen (p.K23-I24insIDK). The aim of the present study was to characterize the effect of this unique genetic alteration on the function of human cationic trypsinogen. Methods: Wild-type and mutant cationic trypsinogens were produced recombinantly and purified to homogeneity. Trypsinogen activation was followed by enzymatic assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Trypsinogen secretion was measured from transfected HEK 293T cells. Results: Recombinant cationic trypsinogen carrying the p.K23-I24insIDK mutation exhibited greater than 10-fold increased autoactivation. Activation by human cathepsin B also was accelerated by 10-fold. Secretion of the p.K23-I24insIDK mutant from transfected cells was diminished, consistent with intracellular autoactivation. Conclusions: This is the first report of an intragenic duplication within the PRSS1 gene causing hereditary pancreatitis. The accelerated activation of p.K23-I24insIDK by cathepsin B is a unique biochemical property not found in any other pancreatitis-associated trypsinogen mutant. In contrast, the robust autoactivation of the novel mutant confirms the notion that increased autoactivation is a disease-relevant mechanism in hereditary pancreatitis.
AB - Objectives: In a hereditary pancreatitis family from Denmark, we identified a novel intragenic duplication of 9 nucleotides in exon-2 of the human cationic trypsinogen (PRSS1) gene (c.63-71dup) which at the amino-acid level resulted in the insertion of 3 amino acids within the activation peptide of cationic trypsinogen (p.K23-I24insIDK). The aim of the present study was to characterize the effect of this unique genetic alteration on the function of human cationic trypsinogen. Methods: Wild-type and mutant cationic trypsinogens were produced recombinantly and purified to homogeneity. Trypsinogen activation was followed by enzymatic assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Trypsinogen secretion was measured from transfected HEK 293T cells. Results: Recombinant cationic trypsinogen carrying the p.K23-I24insIDK mutation exhibited greater than 10-fold increased autoactivation. Activation by human cathepsin B also was accelerated by 10-fold. Secretion of the p.K23-I24insIDK mutant from transfected cells was diminished, consistent with intracellular autoactivation. Conclusions: This is the first report of an intragenic duplication within the PRSS1 gene causing hereditary pancreatitis. The accelerated activation of p.K23-I24insIDK by cathepsin B is a unique biochemical property not found in any other pancreatitis-associated trypsinogen mutant. In contrast, the robust autoactivation of the novel mutant confirms the notion that increased autoactivation is a disease-relevant mechanism in hereditary pancreatitis.
U2 - http://dx.doi.org/10.1097/MPA.0b013e3182152fdf
DO - http://dx.doi.org/10.1097/MPA.0b013e3182152fdf
M3 - Journal article
SN - 0885-3177
VL - 40
SP - 540
EP - 546
JO - Pancreas
JF - Pancreas
IS - 4
ER -
