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Transthyretin amyloid fibril formation: effects of coprecipitation with different transthyretin fragmentS
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TRANSTHYRETIN AMYLOID FIBRIL FORMATION: EFFECTSOF COPRECIRTATION WITH DIFFERENT TRANSTHYRETIN FRAGMENTS Asa Gustavsson 1, Ulla Engstr6m 2 and Per Westermark 1. 1Department of Pathology I, LinkOping University, LinkSping and 2Ludwig Institute of Cancer Research, Uppsala Branch, Uppsala, Sweden. Transthyretin (TFR) is the major amyloid fibril protein in several familial forms of amyloldosis (FAP) and in senile systemic arnyioidosis (SSA). In both forms the amyloid fibdls contain both full-length and fragmented TI'R. In most SSA cases the fibdls contain mostly C-terminal TFR fragments. It is not known if the TI'R molecules are fragmented before or after their incorporation in the amyioid fibrils. The importance of these fragments in the fibrillogenesis is not understood. Using an in vitro system for fibril formation we have studied the coprecipitation of normal TI'R, ATI'R, "nR fragments with different synthetic TTR fragments. The fibrils were studied by electron microscopy and in polarized light microscopy after Congo red staining. These studies show that the formation of fibdls is affected when different forms of TTR are copreciPltated.
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TRANSTHYRETIN FIBRILSAND SYNTHETICPEPTIDEFIBRILS Asa Gustavsson 1, Ulla EngstrOm2 and Per Westermark 1. 1Department of Pathology I, LinkOping University, Link~oing and 2Ludwig Institute of Cancer Research, Uppsala Branch, Uppsala, Sweden. How amyloid fibrils are formed/n vivo is not understood. Fibril formation can be studied in vitro using synthetic peptides corresponding to specific regions of the amyloid protein. The fibril forming capacity of the peptides is examined to see if some part of the amylold protein molecule is more fibrillogenic and possibly important in the in vivo fibdllogenesis. Several synthetic peptides corresponding to different parts of the transthyretin (TrR) molecule were synthesized. The fibril forming capacity of these peptides was investigated. The fibrils formed in this in vitro system were studied with electron microscopy and with polarized Hght after Congo red staining. The fibrils were also compared with amyloid fibrils extracted flora a patient with senile systemic arnyloidosis (SSA). The in vitro formed fibrils and the amyloid fibrils were immunolabeHed with antisera raised against synthetic TrR peptides, amyloid TTR and normal TTR. The synthetic peptides that correspond to parts of the TI'R sequence that are in ~-strand conformation in the tertiary structure were fibdllogenic. Also, a synthetic peptide corresponding to the DE loop and a synthetic peptide corresponding to the ¢zhelix were strongly fibdllogenic in our/n ~ system. The results show that several parts of the TTR molecule have fibril forming capacity in vitro.
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TRANSTHYRETIN AMYLOID FIBRIL FORMATION: EFFECTSOF COPRECIRTATION WITH DIFFERENT TRANSTHYRETIN FRAGMENTS Asa Gustavsson 1, Ulla Engstr6m 2 and Per Westermark 1. 1Department of Pathology I, LinkOping University, LinkSping and 2Ludwig Institute of Cancer Research, Uppsala Branch, Uppsala, Sweden. Transthyretin (TFR) is the major amyloid fibril protein in several familial forms of amyloldosis (FAP) and in senile systemic arnyioidosis (SSA). In both forms the amyloid fibdls contain both full-length and fragmented TI'R. In most SSA cases the fibdls contain mostly C-terminal TFR fragments. It is not known if the TI'R molecules are fragmented before or after their incorporation in the amyioid fibrils. The importance of these fragments in the fibrillogenesis is not understood. Using an in vitro system for fibril formation we have studied the coprecipitation of normal TI'R, ATI'R, "nR fragments with different synthetic TTR fragments. The fibrils were studied by electron microscopy and in polarized light microscopy after Congo red staining. These studies show that the formation of fibdls is affected when different forms of TTR are copreciPltated.
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TRANSTHYRETIN FIBRILSAND SYNTHETICPEPTIDEFIBRILS Asa Gustavsson 1, Ulla EngstrOm2 and Per Westermark 1. 1Department of Pathology I, LinkOping University, Link~oing and 2Ludwig Institute of Cancer Research, Uppsala Branch, Uppsala, Sweden. How amyloid fibrils are formed/n vivo is not understood. Fibril formation can be studied in vitro using synthetic peptides corresponding to specific regions of the amyloid protein. The fibril forming capacity of the peptides is examined to see if some part of the amylold protein molecule is more fibrillogenic and possibly important in the in vivo fibdllogenesis. Several synthetic peptides corresponding to different parts of the transthyretin (TrR) molecule were synthesized. The fibril forming capacity of these peptides was investigated. The fibrils formed in this in vitro system were studied with electron microscopy and with polarized Hght after Congo red staining. The fibrils were also compared with amyloid fibrils extracted flora a patient with senile systemic arnyloidosis (SSA). The in vitro formed fibrils and the amyloid fibrils were immunolabeHed with antisera raised against synthetic TrR peptides, amyloid TTR and normal TTR. The synthetic peptides that correspond to parts of the TI'R sequence that are in ~-strand conformation in the tertiary structure were fibdllogenic. Also, a synthetic peptide corresponding to the DE loop and a synthetic peptide corresponding to the ¢zhelix were strongly fibdllogenic in our/n ~ system. The results show that several parts of the TTR molecule have fibril forming capacity in vitro.