Characterization of the genomic region containing the Shadow of Prion Protein (SPRN) gene in sheep
© Lampo et al; licensee BioMed Central Ltd. 2007
Received: 29 January 2007
Accepted: 30 May 2007
Published: 30 May 2007
TSEs are a group of fatal neurodegenerative diseases occurring in man and animals. They are caused by prions, alternatively folded forms of the endogenous prion protein, encoded by PRNP. Since differences in the sequence of PRNP can not explain all variation in TSE susceptibility, there is growing interest in other genes that might have an influence on this susceptibility. One of these genes is SPRN, a gene coding for a protein showing remarkable similarities with the prion protein. Until now, SPRN has not been described in sheep, a highly relevant species in prion matters.
In order to characterize the genomic region containing SPRN in sheep, a BAC mini-contig was built, covering approximately 200,000 bp and containing the genes ECHS1, PAOX, MTG1, SPRN, LOC619207, CYP2E1 and at least partially SYCE1. FISH mapping of the two most exterior BAC clones of the contig positioned this contig on Oari22q24. A fragment of 4,544 bp was also sequenced, covering the entire SPRN gene and 1206 bp of the promoter region. In addition, the transcription profile of SPRN in 21 tissues was determined by RT-PCR, showing high levels in cerebrum and cerebellum, and low levels in testis, lymph node, jejunum, ileum, colon and rectum.
Annotation of a mini-contig including SPRN suggests conserved linkage between Oari22q24 and Hsap10q26. The ovine SPRN sequence, described for the first time, shows a high level of homology with the bovine, and to a lesser extent with the human SPRN sequence. In addition, transcription profiling in sheep reveals main expression of SPRN in brain tissue, as in rat, cow, man and mouse.
TSEs are a group of fatal neurodegenerative diseases, caused by prions (PrPSc). These infectious particles are alternatively folded forms of the endogenous protein PrPC, encoded by PRNP [1, 2]. Conversion of PrPC into PrPSc requires the presence of PrPSc and probably also of a not identified species-specific protein, 'protein X' [3, 4].
In sheep, TSE susceptibility is influenced by polymorphisms of the PRNP gene, with the alleles coding for alanine, arginine and arginine at positions 136, 154 and 171 of the prion protein associated with a high resistance to classical scrapie and BSE . Nevertheless, this resistance is not absolute, since it has been shown that atypical scrapie can occur in sheep with the genotype ARR/ARR [6–11], sheep with this genotype can be artificially infected with BSE  and infectivity has been detected in the spleen of an ARR/ARR sheep, experimentally infected with BSE . Moreover, the presumed resistance of ARR/ARR sheep might be due to a longer incubation period in these animals and subclinically infected sheep might transmit TSE infections unnoticed [14, 15]. Therefore, there is growing interest in other genes and proteins which could have an influence on TSE susceptibility in sheep.
One of these genes is PRND, a PRNP homologue found near the PRNP gene and having structural and biochemical similarities with PRNP. However, no clear influence of PRND on TSE susceptibility has been found to date [16, 17]. Also, a number of proteins with a high affinity for the prion protein, among which the 37-kDa/67-kDa laminin receptor, have been discovered [18, 19] and could be important as 'protein X' candidates. In addition, gene expression studies in the brain of scrapie-infected mice have identified a large number of genes, potentially involved in the pathogenesis of TSEs [20–22].
Based on comparative genomics, Premzl et al.  have discovered SPRN, a new candidate gene which codes for the Shadoo protein of 130–150 amino acids. This gene has already been described in man, mouse, rat, fish  and cow  and is predicted in chimpanzee (GenBank:XM_001146049). The Shadoo protein has also been identified in Sumatran orang-utan, rhesus macaque, white-tufted-ear marmoset, rabbit, guinea pig, dog, little brown bat, gray short-tailed opossum, chicken and western clawed frog . An evolutionary model proposes that SPRN shares a common ancestor with PRNP , since it presents several important similarities with PRNP. First, the open reading frame of SPRN is located entirely in the last exon, with one preceding non-coding exon (one or two in PRNP) [23, 27]. In addition, Shadoo is predicted to be extracellular and glycosylphosphatidylinositol-anchored. Moreover, the most remarkable structural feature of Shadoo is the presence of a hydrophobic sequence, composed of aliphatic amino acids and very similar to the hydrophobic sequence typically found in PrP and PrP-like proteins [23, 28, 29].
Apart from the structural similarities between SPRN and PRNP, the expression profile of SPRN also makes this gene an interesting candidate for further research. According to the results of RT-PCR and Northern blot analyses in cow , RT-PCR in rat , and cDNA, EST and SAGE map data in man and mouse , SPRN is mainly expressed in brain tissue, the most important target organ for prion infections. Since PrP knock-out mice  and cattle lacking the prion protein  show no major phenotypic changes, another gene, possibly SPRN, might take over the physiological function of the prion protein.
In this study, the genomic region containing SPRN in sheep was investigated using comparative mapping and sequencing and transcription profiling of the SPRN gene were performed.
Results and discussion
Construction and annotation of a BAC mini-contig containing SPRN
Characteristics of the BESs.
Length sequence (bp)
Annotation (repeats (class/family) or
nucleic acid identity with described sequences)
No repeats, no homology found
Cow: NM_001076278: 91%
Man: AL360181: 91%
21–173: L1M4 (LINE/L1)
160–752: BovB (LINE/RTE)
29–823: L1MA4A (LINE/L1)
114–257: MER34A1 (LTR/ERV1)
318–426: L1MC3 (LINE/L1)
498–688: L1MC3 (LINE1/L1)
246–278: TGGG(n) (simple repeat)
No repeats, no homology found
Cow: DQ058603: 89%
Cow: DQ058602: 89%
1–210: BovB (LINE/RTE)
Amplicon characteristics of primers used for the annotation of the contig and the transcription profiling.
Gene symbol or primer's name
Forward primer (5'-3')
Reverse primer (5'-3')
Accession number amplicons
% nucleic acid identity/amino acid identity/amino acid positivity with described sequences
OariEST (CD288818): 96/93/94
BtauECHS1 (DQ058603): 96/87/94
HsapECHS1 (NM_004092): 86/80/92
OariEST (DY499183): 99/100/100
BtauPAOX (DQ058602): 95/98/100
HsapPAOX (NM_152911): 90/88/94
BtauMTG1 (DQ058604): 92/75/85
BtauSPRN (DQ058606): 95/92/93
HsapSPRN (NM_001012508): 79/76/80
HsapLOC619207 (NT_017795): 88/73/84
OariEST (EE790798): 98/100/100
BtauCYP2E1 (DQ058608): 98/97/100
HsapCYP2E1 (NM_000773): 91/86/94
HsapSYCE1 (NT_017795): 90/90/90
Order as well as orientation of the identified genes present in the sheep contig are identical to those of the corresponding region in man (Hsap10q26; human genome sequence), supporting conserved linkage between these species. In cattle, PAOX has an opposite orientation (Btau26q23; ). Remarkably, the block ECHS1, PAOX, MTG1 and SPRN seems highly conserved, as it is also found in man, mouse and even fugu . The scavenger receptor close to SPRN in man and mouse, mentioned by Premzl et al. , is probably LOC619207 (as it codes for a scavenger receptor protein family member), and is therefore also present in the sheep contig.
FISH mapping of the contig
Sequencing SPRN in sheep
Amplicon characteristics of the SPRN primers used.
Number SPRN primers
Forward primer (5'-3')
Reverse primer (5'-3')
Position in sequence DQ870545
The coding sequence of sheep SPRN has 93% respectively 78% nucleic acid identity, and 95% respectively 76% amino acid identity with cow and man. The complete sequence obtained here (Genbank:DQ870545) has 92% nucleic acid identity with the bovine SPRN sequence (Genbank:DQ058606). The GC content of the coding sequence in sheep is high (79%), as in cow (77%) and man (79%). The overall GC content of the obtained SPRN sequence in sheep is 70%.
Transcription profiling of SPRN by RT-PCR
These results of the transcription profiling in sheep are in good agreement with the data available in other species. Results of RT-PCR and Northern blot analyses in cattle , RT-PCR in rat  and cDNA, EST and SAGE map data analyses in man and mouse  all show that expression of SPRN is highest in brain tissue. Comparison of the SPRN transcription profile of the non-brain tissues between sheep and other species is more difficult, as the transcription level is lower in the other positive tissues, in sheep as well as in cow and rat.
Transcription profiling was performed by RT-PCR. This method permits the rapid testing of a large number of different tissues for the presence of a certain transcript. RT-PCR does not give detailed quantitative information on expression, therefore more time consuming methods like real-time PCR or real competitive PCR are needed . However, RT-PCR results give an overall view and can be the basis to choose tissues of interest for more extended, quantitative experiments.
In this study, SPRN as well as six genes surrounding the SPRN locus, ECHS1,PAOX,MTG1,LOC619207,CYP2E1 and SYCE1, have been identified in sheep for the first time. A contig containing these genes was constructed and annotated, suggesting conserved linkage between sheep and man in this region. The contig was FISH mapped to Oari22q24. A 4,544 bp fragment was also sequenced, covering the entire SPRN gene and 1206 bp of the promoter region. A high level of sequence homology was found with the bovine SPRN and, to a lesser extent, with the human SPRN. In addition, the transcription profile of SPRN was determined in 21 ovine tissues, confirming that SPRN is mainly expressed in brain tissue. These results are the first description of the SPRN gene in sheep and should be useful as a basis for further research on this prion-like protein.
Primer design and PCR
Primers were designed with Primer3  based on sequences found in NCBI Entrez Gene  or on BESs, and all amplicons were verified by sequencing. A list of the primers used with their conditions is given in Tables 2 and 3. PCR was performed with 0.5 U Faststart Taq DNA Polymerase (Roche), 2.0 mM Mg and 200 μM (each) dNTPs (Bioline) on 200 ng BAC DNA, 20–200 ng RNA or on reverse transcribed RNA. For the amplification of SPRN sequences, a 5x solution of GC-rich (supplied with the Faststart Taq DNA Polymerase) was added. PCR conditions were 5 min at 95°C, 40 cycles of 30 s at 95°C, 30 s at the annealing temperature and 1 min at 72°C, and a final 10 min elongation at 72°C.
Construction and annotation of a BAC contig
Primers for the genes PAOX and CYP2E1 were used for the initial screening of the INRA ovine BAC library by PCR . BAC DNA from three isolated BAC clones was purified from 200 ml culture using the Qiagen Plasmid Midi kit (Qiagen) and the BAC ends were sequenced with UP and RP, using 1 μg DNA per reaction. Primers designed on the BESs of the isolated BAC clones were used to find overlaps between these BAC clones and the OariBAC273H7 UP primers were used to screen the INRA ovine BAC library for new BAC clones in order to close the gap between the two subcontigs. Annotation of the contig was performed by comparing BESs with the human genome sequence and by PCR with primers for genes presumed to be present in the contig. Comparisons were done with NCBI Blast  and repeat sequences were detected and identified with Repeatmasker Web Server .
For probe preparation, BAC DNA extracts were prepared according to standard protocols and purified with the S.N.A.P. K1900-01 Miniprep kit (Invitrogen life technologies). DNA was then labelled by nick-translation with biotin-14-dATP (BioNick 18247-015 labelling system, Invitrogen life technologies), mixed with 100x total sonicated herring sperm DNA and 100x total sonicated sheep DNA, ethanol precipitated, slightly dried and resuspended in hybridization buffer.
R-banded chromosome spreads were obtained from sheep embryo fibroblast cell cultures synchronized with an excess of thymidine and treated with 5-bromodeoxyuridine during the second half of S phase . Fluorescent in situ hybridization, signal detection and R-banding were performed as previously described  with 50–100 ng of biotin-14-dATP labelled probe per slide. Before hybridization to the chromosomes, probes were denatured at 100°C for 10 min and pre-hybridized at 37°C for 30–60 min. Slides were examined under a Zeiss Axioplan 2 epifluorescence microscope and the Applied Imaging Cytovision (version 2.7) software was used for image capturing and analysis. Chromosome identification and band nomenclature for sheep chromosomes follow the R-banded standard ideogram reported in ISCNDB2000 .
For sequencing SPRN in sheep, the primers mentioned in Table 3 were used. Amplicons of the SPRN primers no. 2, 3, 4 and 5 were cloned and sequenced with UP and RP. The other amplicons were sequenced by direct sequencing.
The 3' end of the ovine SPRN sequence was obtained using mRNA from cerebrum tissue, isolated with the Illustra™ Quickprep Micro mRNA Purification kit according to the manufacturer's protocol. The obtained mRNA then was converted into cDNA with the Improm-II Reverse Transcriptase kit (Promega) using a newly designed oligo dT primer (SPRN primer no. 18) which adds 42 bp to the cDNA. Finally, a PCR with SPRN primers no. 16, followed by a PCR with the nested SPRN primers no. 17 (both creating an amplicon including the polyA sequence) was performed on 10x diluted cDNA and the obtained amplicon was directly sequenced with SPRN primers no. 17.
All sequencing was performed on a Applied Biosystems 3730xl DNA Analyser with the BigDye Terminator v3.1 Cycle Sequencing Kit (Applied Biosystems).
RNA isolation, cDNA synthesis and RT-PCR
Tissues for RNA isolation were collected in a commercial sheep slaughterhouse, immediately frozen in liquid nitrogen, crushed to powder the same day and stored at -80°C. Total RNA was isolated with the Rneasy plus mini kit (Qiagen) on 30 mg tissue, except for heart, muscle and tongue, where TRIR (ABgene) and 80–100 mg tissue were used. Both methods were performed according to the manufacturer's protocol and followed by a DNase treatment with RQ1 RNase-free DNase (Promega) and a spin-column purification with Microcon YM-100 (Millipore), according to the product's user guides. RNA concentration and OD260/280 ratio of the samples were measured with the Nanodrop ND-1000 Spectrophotometer (Isogen) and RNA quality was measured by evaluation of the 28S and the 18S ribosomal bands on a 0.8% agarose gel. Also, a minus RT-PCR was performed on 1 μl RNA to confirm the absence of any DNA contamination. After RNA controls, 0.2–1 μg RNA was converted into cDNA with the Improm-II Reverse Transcriptase kit (Promega) using Random and Oligo dT primers (each 0.5 μg per reaction), and the conversion was confirmed by a PCR with ACTB primers (giving an amplicon of different length on gDNA and cDNA) on 10x diluted cDNA. Determination of the transcription profile of SPRN was performed with SPRN primers no. 9 and SPRN primers no. 11 on 10x diluted cDNA.
List of abbreviations
- ACTB :
gene coding for actin-beta
genotype of PRNP coding for alanine-arginine-arginine at positions 136, 154 and 171 of PrP
bacterial artificial chromosome
BAC end sequence
bovine spongiform encephalopathy
- CYP2E1 :
gene coding for cytochrome P450, family 2, subfamily E, polypeptide 1
- ECHS1 :
gene coding for enoyl Coenzyme A hydratase, short chain, 1, mitochondrial
expressed sequence tag
fluorescence in situ hybridization
high throughput genomic sequence
long interspersed nuclear element
- LOC619207 :
gene coding for scavenger receptor protein family member
long terminal repeat
- MTG1 :
gene coding for mitochondrial GTPase 1 homolog (S. cerevisiae)
- PAOX :
gene coding for polyamine oxidase (exo-N4-amino)
polymerase chain reaction
- PRND :
gene coding for prion protein 2 (dublet)
- PRNP :
gene coding for prion protein
cellular form of the prion protein
disease causing form of the prion protein
serial analysis of gene expression
- SPRN :
gene coding for Shadow of prion protein
- SYCE1 :
gene coding for synaptonemal complex central element protein 1
transmissible spongiform encephalopathy
The authors wish to thank Dominique Vander Donckt, Céline Ducroix-Crépy, Maud Bertaud and Elien Imant for excellent technical assistance. Evelyne Lampo is Research Assistant of the Research Foundation-Flanders (FWO).
- Prusiner SB: Prions. Proc Natl Acad Sci USA. 1998, 95: 13363-13383. 10.1073/pnas.95.23.13363.PubMed CentralPubMedView ArticleGoogle Scholar
- Dalsgaard NJ: Prion diseases. An overview. APMIS. 2002, 110: 3-13. 10.1034/j.1600-0463.2002.100102.x.PubMedView ArticleGoogle Scholar
- Fasano C, Campana V, Zurzolo C: Prions: protein only or something more? Overview of potential prion cofactors. J Mol Neurosci. 2006, 29: 195-214. 10.1385/JMN:29:3:195.PubMedView ArticleGoogle Scholar
- Kaneko K, Zulianello L, Scott M, Cooper CM, Wallace AC, James TL, Cohen FE, Prusiner SB: Evidence for protein X binding to a discontinuous epitope on the cellular prion protein during scrapie prion propagation. Proc Natl Acad Sci USA. 1997, 94: 10069-10074. 10.1073/pnas.94.19.10069.PubMed CentralPubMedView ArticleGoogle Scholar
- Hunter N: Scrapie and experimental BSE in sheep. Br Med Bull. 2003, 66: 171-183. 10.1093/bmb/66.1.171.PubMedView ArticleGoogle Scholar
- Buschmann A, Luhken G, Schultz J, Erhardt G, Groschup MH: Neuronal accumulation of abnormal prion protein in sheep carrying a scrapie-resistant genotype (PrPARR/ARR). J Gen Virol. 2004, 85: 2727-2733. 10.1099/vir.0.79997-0.PubMedView ArticleGoogle Scholar
- Madec JY, Simon S, Lezmi S, Bencsik A, Grassi J, Baron T: Abnormal prion protein in genetically resistant sheep from a scrapie-infected flock. J Gen Virol. 2004, 85: 3483-3486. 10.1099/vir.0.80220-0.PubMedView ArticleGoogle Scholar
- Orge L, Galo A, Machado C, Lima C, Ochoa C, Silva J, Ramos M, Simas JP: Identification of putative atypical scrapie in sheep in Portugal. J Gen Virol. 2004, 85: 3487-3491. 10.1099/vir.0.80246-0.PubMedView ArticleGoogle Scholar
- De Bosschere H, Roels S, Dechamps P, Vanopdenbosch E: TSE detected in a Belgian ARR-homozygous sheep via active surveillance. Vet J. 2007, 173: 449-451. 10.1016/j.tvjl.2005.07.014.PubMedView ArticleGoogle Scholar
- Le Dur A, Beringue V, Andréoletti O, Reine F, Lai TL, Baron T, Bratberg B, Vilotte JL, Sarradin P, Benestad SL, Laude H: A newly identified type of scrapie agent can naturally infect sheep with resistant PrP genotypes. Proc Natl Acad Sci USA. 2005, 102: 16031-16036. 10.1073/pnas.0502296102.PubMed CentralPubMedView ArticleGoogle Scholar
- Saunders GC, Cawthraw S, Mountjoy SJ, Hope J, Windl O: PrP genotypes of atypical scrapie cases in Great Britain. J Gen Virol. 2006, 87: 3141-3149. 10.1099/vir.0.81779-0.PubMedView ArticleGoogle Scholar
- Houston F, Goldmann W, Chong A, Jeffrey M, Gonzalez L, Foster J, Parnham D, Hunter N: Prion diseases: BSE in sheep bred for resistance to infection. Nature. 2003, 423: 498-10.1038/423498a.PubMedView ArticleGoogle Scholar
- Andréoletti O, Morel N, Lacroux C, Rouillon V, Barc C, Tabouret G, Sarradin P, Berthon P, Bernardet P, Mathey J, Lugan S, Costes P, Corbiere F, Espinosa JC, Torres JM, Grassi J, Schelcher F, Lantier F: Bovine spongiform encephalopathy agent in spleen from an ARR/ARR orally exposed sheep. J Gen Virol. 2006, 87: 1043-1046. 10.1099/vir.0.81318-0.PubMedView ArticleGoogle Scholar
- Hill AF, Collinge J: Subclinical prion infection in humans and animals. Br Med Bull. 2003, 66: 161-170. 10.1093/bmb/66.1.161.PubMedView ArticleGoogle Scholar
- Thackray AM, Klein MA, Bujdoso R: Subclinical prion disease induced by oral inoculation. J Virol. 2003, 77: 7991-7998. 10.1128/JVI.77.14.7991-7998.2003.PubMed CentralPubMedView ArticleGoogle Scholar
- Golinska E, Flirski M, Liberski PP: Doppel: the prion's double. Folia Neuropathol. 2004, 42 (Suppl A): 47-54.Google Scholar
- Qin K, O'Donnell M, Zhao RY: Doppel: more rival than double to prion. Neuroscience. 2006, 141: 1-8. 10.1016/j.neuroscience.2006.04.057.PubMedView ArticleGoogle Scholar
- Hundt C, Peyrin JM, Haik S, Gauczynski S, Leucht C, Rieger R, Riley ML, Deslys JP, Dormont D, Lasmezas CI, Weiss S: Identification of interaction domains of the prion protein with its 37-kDa/67-kDa laminin receptor. EMBO J. 2001, 20: 5876-5886. 10.1093/emboj/20.21.5876.PubMed CentralPubMedView ArticleGoogle Scholar
- Petrakis S, Sklaviadis T: Identification of proteins with high affinity for refolded and native PrP(C). Proteomics. 2006, 6: 6476-6484. 10.1002/pmic.200600103.PubMedView ArticleGoogle Scholar
- Xiang W, Windl O, Wunsch G, Dugas M, Kohlmann A, Dierkes N, Westner IM, Kretschmar HA: Identification of differentially expressed genes in scrapie-infected mouse brains by using global gene expression technology. J Virol. 2004, 78: 11051-11060. 10.1128/JVI.78.20.11051-11060.2004.PubMed CentralPubMedView ArticleGoogle Scholar
- Brown AR, Rebus S, McKimmie CS, Robertson K, Williams A, Fazakerley JK: Gene expression profiling of the preclinical scrapie-infected hippocampus. Biochem Biophys Res Commun. 2005, 334 (1): 86-95. 10.1016/j.bbrc.2005.06.060.PubMedView ArticleGoogle Scholar
- Skinner PJ, Abbassi H, Chesebro B, Race RE, Reilly C, Haase AT: Gene expression alterations in brains of mice infected with three strains of scrapie. BMC Genomics. 2006, 7: 114-10.1186/1471-2164-7-114.PubMed CentralPubMedView ArticleGoogle Scholar
- Premzl M, Sangiorgio L, Strumbo B, Marshall Graves JA, Simonic T, Gready JE: Shadoo, a new protein highly conserved from fish to mammals and with similarity to prion protein. Gene. 2003, 314: 89-102. 10.1016/S0378-1119(03)00707-8.PubMedView ArticleGoogle Scholar
- Uboldi C, Paulis M, Guidi E, Bertoni A, Meo GP, Perucatti A, Iannuzzi L, Raimondi E, Brunner RM, Eggen A, Ferretti L: Cloning of the bovine prion-like Shadoo (SPRN) gene by comparative analysis of the predicted genomic locus. Mamm Genome. 2006, 17: 1130-1139. 10.1007/s00335-006-0078-7.PubMedView ArticleGoogle Scholar
- Premzl M, Gamulin V: Comparative genomic analysis of prion genes. BMC Genomics. 2007, 8: 1-10.1186/1471-2164-8-1.PubMed CentralPubMedView ArticleGoogle Scholar
- Premzl M, Gready JE, Jermiin LS, Simonic T, Marshall Graves JA: Evolution of vertebrate genes related to prion and Shadoo proteins-clues from comparative genomic analysis. Mol Biol Evol. 2004, 21: 2210-2231. 10.1093/molbev/msh245.PubMedView ArticleGoogle Scholar
- Lee IY, Westaway D, Smit AF, Wang K, Seto J, Chen L, Acharya C, Ankener M, Baskin D, Cooper C, Yao H, Prusiner SB, Hood LE: Complete genomic sequence and analysis of the prion protein gene region from three mammalian species. Genome Res. 1998, 8: 1022-1037.PubMedView ArticleGoogle Scholar
- Oidtmann B, Simon D, Holtkamp N, Hoffmann R, Baier M: Identification of cDNAs from Japanese pufferfish (Fugu rubripes) and Atlantic salmon (Salmo salar) coding for homologues to tetrapod prion proteins. FEBS Lett. 2003, 538: 96-100. 10.1016/S0014-5793(03)00149-2.PubMedView ArticleGoogle Scholar
- Suzuki T, Kurokawa T, Hashimoto H, Sugiyama M: cDNA sequence and tissue expression of Fugu rubripes prion protein-like: a candidate for the teleost orthologue of tetrapod PrPs. Biochem Biophys Res Commun. 2002, 294: 912-917. 10.1016/S0006-291X(02)00546-6.PubMedView ArticleGoogle Scholar
- Büeler H, Fischer M, Lang Y, Bluethmann H, Lipp H-P, DeArmond SJ, Prusiner SB, Aguet M, Weissmann C: Normal development and behaviour of mice lacking the neuronal cell-surface PrP protein. Nature. 1992, 356: 577-582. 10.1038/356577a0.PubMedView ArticleGoogle Scholar
- Richt JA, Kasinathan P, Hamir AN, Castilla J, Sathiyaseelan T, Vargas F, Sathiyaseelan J, Wu H, Matsushita H, Koster J, Kato S, Ishida I, Soto C, Robl JM, Kuroiwa Y: Production of cattle lacking prion protein. Nat Biotechnol. 2007, 25: 132-138. 10.1038/nbt1271.PubMed CentralPubMedView ArticleGoogle Scholar
- Iannuzzi L, Di Meo GP, Perucatti A, Incarnato D: Comparison of the human with the sheep genome by use of human chromosome-specific painting probes. Mamm Genome. 1999, 10: 719-723. 10.1007/s003359901078.PubMedView ArticleGoogle Scholar
- Schatzl HM, Da Costa M, Taylor L, Cohen FE, Prusiner SB: Prion protein variation among primates. J Mol Biol. 1995, 245: 362-374. 10.1006/jmbi.1994.0030.PubMedView ArticleGoogle Scholar
- Bergström AL, Cordes H, Zsurger N, Heegaard PM, Laursen H, Chabry J: Amidation and structure relaxation abolish the neurotoxicity of the prion peptide PrP106-126 in vivo and in vitro. J Biol Chem. 2005, 280: 23114-23121. 10.1074/jbc.M500210200.PubMedView ArticleGoogle Scholar
- Fioriti L, Quaglio E, Massignan T, Colombo L, Stewart RS, Salmona M, Harris DA, Forloni G, Chiesa R: The neurotoxicity of prion protein (PrP) peptide 106–126 is independent of the expression level of PrP and is not mediated by abnormal PrP species. Mol Cell Neurosci. 2005, 28: 165-176. 10.1016/j.mcn.2004.09.006.PubMedView ArticleGoogle Scholar
- Jobling MF, Stewart LR, White AR, McLean C, Friedhuber A, Maher F, Beyreuther K, Masters CL, Barrow CJ, Collins SJ, Cappai R: The hydrophobic core sequence modulates the neurotoxic and secondary structure properties of the prion peptide 106–126. J Neurochem. 1999, 73: 1557-1565. 10.1046/j.1471-4159.1999.0731557.x.PubMedView ArticleGoogle Scholar
- Norstrom EM, Mastrianni JA: The AGAAAAGA palindrome in PrP is required to generate a productive PrPSc-PrPC complex that leads to prion propagation. J Biol Chem. 2005, 280: 27236-27243. 10.1074/jbc.M413441200.PubMedView ArticleGoogle Scholar
- Brown R: PrPSc-like prion protein peptide inhibits the function of cellular prion protein. Biochem J. 2000, 352: 511-518. 10.1042/0264-6021:3520511.PubMed CentralPubMedView ArticleGoogle Scholar
- Ding C, Cantor CR: Quantitative analysis of nucleic acids – the last few years of progress. J Biochem Mol Biol. 2004, 37: 1-10.PubMedView ArticleGoogle Scholar
- Rozen S, Skaletsky HJ: Primer3 on the WWW for general users and for biologist programmers. Bioinformatics Methods and Protocols: Methods in Molecular Biology. Edited by: Krawetz S, Misener S. 2000, Totowa: Humana Press, 365-386. [http://frodo.wi.mit.edu/cgi-bin/primer3/primer3_www.cgi]Google Scholar
- NCBI Entrez Gene. [http://www.ncbi.nlm.nih.gov/gquery/gquery.fcgi?otool=ibeuglib&otool=ibeuglib]
- Vaiman D, Billault A, Tabet-Aoul K, Schibler L, Vilette D, Oustry-Vaiman A, Soravito C, Cribiu EP: Construction and characterization of a sheep BAC library of three genome equivalents. Mamm Genome. 1999, 10: 585-587. 10.1007/s003359901049.PubMedView ArticleGoogle Scholar
- Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ: Basic local alignment search tool. J Mol Biol. 1990, 215: 403-410. [http://www.ncbi.nlm.nih.gov/BLAST/]PubMedView ArticleGoogle Scholar
- Repeatmasker Webserver (Institute for SystemsBiology). [http://www.repeatmasker.org/cgi-bin/WEBRepeatMasker]
- Hayes H, Petit E, Dutrillaux B: Comparison of RBG-banded karyotypes of cattle, sheep, and goats. Cytogenet Cell Genet. 1991, 57: 51-55.PubMedView ArticleGoogle Scholar
- Hayes H, Petit E, Lemieux N, Dutrillaux B: Chromosomal localization of the ovine beta-casein gene by non-isotopic in situ hybridization and R-banding. Cytogenet Cell Genet. 1992, 61: 286-288.PubMedView ArticleGoogle Scholar
- Cribiu EP, Di Berardino D, Di Meo GP, Eggen A, Gallagher DS, Gustavsson I, Hayes H, Iannuzzi L, Popescu CP, Rubes J, Schmutz S, Stranzinger G, Vaiman A, Womack J: International System for Chromosome Nomenclature of Domestic Bovids (ISCNBD 2000). Cytogenet Cell Genet. 2001, 92: 283-299. 10.1159/000056917.PubMedView ArticleGoogle Scholar
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