NR AKCG
AU Rogers,M.; Yehiely,F.; Scott,M.R.D.; Prusiner,S.B.
TI Conversion of truncated and elongated prion proteins into the scrapie isoform in cultured cells
QU Proceedings of the National Academy of Sciences of the United States of America 1993 Apr 15; 90(8): 3182-6
IA http://www.pnas.org/cgi/reprint/90/8/3182
PT journal article
AB The only known component of the infectious prion is a posttranslationally modified protein known as the scrapie isoform of the prion protein, PrPsc. Upon limited proteolysis, a protease-resistant fragment designated PrP 27-30 is formed. Using in vitro mutagenesis, we examined the role of the N and C termini in the formation of PrPsc in persistently infected, mouse neuroblastoma (ScN2a) cells. Neither deletion of amino acids 23-88, which are also removed by proteinase K in the formation of PrP 27-30, nor deletion of the five octapeptide repeats within this region altered synthesis of PrPsc. Elongation of PrP with one, two, four, or six octapeptide repeats in addition to the five found in wild-type PrP did not alter the synthesis of PrPsc. Truncation of the C terminus was accomplished by substituting a translation stop codon for the predicted glycosylinositol phospholipid (GPI) anchor-attachment signal corresponding to amino acids 231-254. Expression of this C-terminal PrP mutant in ScN2a cells produced PrPsc that appeared to lack a GPI anchor. We conclude that neither the GPI anchor nor the N-terminal 66 amino acids are required for the synthesis of PrPsc as measured by the acquisition of limited resistance to proteinase K digestion. Whether these truncated or elongated PrP molecules are competent to participate in the formation of infectious prions remains to be established.
IN Die einzige bekannte Komponente der infektiösen Prione ist die posttranslational durch Proteolyse auf 27-30 kDa verkürzte und daher proteaseresistente Scrapie-Isoform des Prionproteins. Durch in vitro Mutagenese wurden Mausneuroblastomzellen erzeugt, deren Prionproteinen die Aminosäuren 23-88 oder die fünf Oktapeptide fehlten, oder 6, 7, 9 oder 11 anstatt 5 Oktapeptide besaßen. Trotz dieser Deletionen bzw. Insertionen konnten die Prionproteine in die proteaseresistente Scrapieisoform überführt werden. Selbst eine Deletion der 66 carboxyterminalen Aminosäuren einschließlich der Signalsequenz der Aminosären 231-254 für den Glycosylinositolphospholipid-Anker verhinderte nicht diese Umwandlung, scheint deren Effizienz aber stark reduziert zu haben. Die Fähigkeit dieser manipulierten Prionproteine zur Bildung von infektiösen Prionen wurde aber noch nicht nachgewiesen.
MH Amino Acid Sequence; Animal; Base Sequence; Chimera; *Genes, Viral; Glycosylphosphatidylinositols/analysis; Hamsters; Mesocricetus; Mice; Molecular Sequence Data; Neuroblastoma; Oligodeoxyribonucleotides; Prions/*genetics/isolation & purification/*metabolism; Recombination, Genetic; Repetitive Sequences, Nucleic Acid; Restriction Mapping; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Tumor Cells, Cultured
AD Department of Neurology, University of California, San Francisco 94143.
SP englisch
PO USA
OR Prion-Krankheiten 7
ZF grobe Zusammenfassung von Roland Heynkes