Infectious amyloid precursor genesequences inprimates usedfor experimental transmission ofhumanspongiform encephalopathy

Based ontheanalysis ofgenomic DNAfrom single healthy animals ofeachoffive primate species, nucleo- tideandpredicted aminoacidsequences oftheinfectious amyloid precursor geneofhigher apes(Gorilla andPan)and OldWorld(Macaca) andNewWorld(Ateles, SaiMni) monkeys showed 95-99%homology tothehumansequences, corre- sponding totheir phylogenetic distance fromhumans. Twoof 18aminoacids thatdiffered fromhumansresulted from nucleotide changes atsites ofmutations inhumans with familial forms ofspongiform encephalopathy (adeleted codonwithin thecodon 51-91region of24bprepeats andasubstitution at codon198). Ineachofthefive animals, codon129specifled methionine, themorecommonofthetwopolymorphic geno- ypes inhumans. Because genotypic homology didnotcorrelate withexperimental transmission rates ofhumanspongiform encephalopathy, primary structural similarity oftheinfectious amyloid precursor protein inhumansandexperimental pri- mates maynotbeanimportant factor indisease tranii- bility. Thehumanspongiform encephalopathies havebeenexperi- mentally transmitted withvarying success tonumerous pri- mateandnonprimate species, including higher apes, mon- keys, prosimians, ruminants, felines, androdents. Genetic differences mightinfluence theeasewithwhichhuman spongiform ecephalopathy canbeexperimentally transmit- ted, andthediscovery andsequencing ofthehumangeneon chromosome 20that encodes thepathogenetic amyloid pro- tein hasmadeitpossible totest thethesis. Wereport here the genesequences offive different nonhuman primate species andcompare thedegree ofhomology withhumans toexper- imental transmission rates foreachinoculated species.§ MATERIALSANDMETHODS Genomic DNA wasextracted fromfrozen brain tissue taken fromasingle healthy animal ofeachofthefollowing primate species: gorilla (Gorilla gorilla), chimpanzee (Pantroglo- dytes), OldWorldrhesus monkey(Macaca mulatta), New Worldspider monkey(Ateles paniscus/fusciceps), andNew Worldsquirrel monkey(Saimiri sciureus). Twooverlapping fragments oftheopenreading frame oftheinfectious amyloid precursor genewereamplified byPCRusing Taqpolymerase andtwosets ofoligonucleotide primers: 5'-TAC TGAGAA TTCATGGCGAAC CTTGGCTACTGG-3' and5'-TAC TGATCTAGATGCTCATGGCACTTCCCAGCAT-3' (for the5'fragment), and5'-TAC TGAGCGGCCGCCAAC ATGAAG CACATGGCTGGT-3' and5'-TAC TGAGTC GACCCTTCCTCATCCCACTATCAGG-3'(for the3' fragment). Generated fragments wereligated intoplasmid