Somatic cell mutations in cerebral tissue of cattle affected by bovine spongiform encephalopathy

Matteo Busconi, Corrado Fogher

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DOI: 10.4236/as.2010.11005                

Abstract

In animals the prion disease includes sheep and goat scrapie and the bovine spongiform encephalopathy (BSE). While several polymorphisms of the prion (PRNP) gene have been identified in sheep and some of them have been associated with susceptibility to scrapie, few mutations are reported in cattle and no correlation with BSE have been demonstrated. Genetic screening for mutants in the PRNP gene of 21 BSE positive animals by direct sequencing of the amplified gene, using DNA extracted from brain as template, confirmed that only few polymorphisms are present. However DNA molecules cloned and sequenced from the population of fragments considering a total of 90 clones from 9 BSE positive and 70 clones from 7 BSE negative animals, gave a highly significant differences in the frequency of mutations (p = 0.01). The high frequency and type of variants found cannot be explained only with misincorporation error of the Taq polymerase. Interestingly one of the mutations found in the BSE positive animals (F209S) corresponds to a mutant that causes a familiar form of prion disease in humans (F198S). These data can be explained with the presence of somatic mutations modifying the PRNP gene in single brain cells.

Keywords

BSE; Prion; Somatic Mutations

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Prusiner, S.B. (1982) Novel proteinaceous infectious particles cause scrapie. Science, 216(4542), 136-144.
[2]	Will, R.G. (1998) Oral infection by the bovine spongiform encephalopathy prion. In: Brown, F., Griffiths, E., Horaud, F. and Petricciani, J.C., Ed., Safety of Biological Products Prepared from Mammalian Cell Culture, Karger Publishers, Basel, 79-84.
[3]	Will, R.G., Alperovitch, A., Poser, S., Pocchiari, M., Hofman, A., Mitrova, E., de Silva, R., D’Alessandro, M., Delasnerie-Laupretre, N., Zerr, I. and van Duijn, C. (1998) Descriptive epidemiology of Creutzfeldt-Jakob disease in six European countries, 1993-1995. Annals of Neurology, 43(6), 763-767.
[4]	Brown, P., Preece, M.A. and Will, R.G. (1992) “Friendly fire” in medicine: Hormones, homografts, and Creutzfeldt-Jakob disease. Lancet, 340(8810), 24-27.
[5]	Hunter, N. (1997) PrP genetics in sheep and the implications for scrapie and BSE. Trends in Microbiology, 5(8), 331-334.
[6]	Heaton, M.P., Leymaster, K.A., Freking, B.A., Hawk, D.A., Smith, T.P.L., Keele, J.W., Snelling, W.M., Fox, J.M., Chitko-McKown, C.G. and Laegreid, W.W. (2003) Prion gene sequence variation within diverse groups of US sheep, beef cattle, and deer. Mammalian Genome, 14(11), 765-777.
[7]	Mastrangelo, P. and Westaway, D. (2001) The prion gene complex encoding PrP(C) and Doppel: Insights from mutational analysis. Gene, 275(1), 1-18.
[8]	Belt, P.B., Muileman, I.H., Schreuder, B.E., Bos-de Ruijter, J., Gielkens, A.L. and Smits, M.A. (1995) Identification of five allelic variants of the sheep PrP gene and their association with natural scrapie. Journal of General Virology, 76, 509-517.
[9]	Neibergs, H.L., Ryan, A.M., Womack, J.E., Spooner, R.L. and Williams, J.L. (1994) Polymorphism analysis of the prion gene in BSE-affected and unaffected cattle. Animal Genetics, 25(5), 313-317.
[10]	Hills, D., Schlaepfer, J., Comincini, S., MacLean, I., Dolf, G., Ferretti, L., Olsaker, I. and Williams, J.L. (2003) Sequence variation in the bovine and ovine PRNP genes. Animal Genetics, 34(3), 183-190.
[11]	Hunter, N., Goldmann, W., Smith, G. and Hope, J. (1994) Frequencies of PrP gene variants in healthy cattle and cattle affected by BSE in Scotland. The Veterinary Record, 135, 400-403.
[12]	Collinge, J., Sidle, K.C.L., Meads, J., Ironside, J. and Hill, A. F. (1996) Molecular analysis of prion strain variation and the aetiology of “new variant” CJD. Nature, 383(6602), 685-690.
[13]	Casalone, C., Zanusso, G., Acutis, P.L., Ferrari, S., Capucci, L., Tagliavini, F., Monaco, S. and Caramelli, M. (2004) Identification of a second bovine amyloidotic spongiform encephalopathy: Molecular similarities with sporadic Creutzfeldt-Jakob disease. Proceedings of the National Academy of Sciences of the United States of America, 101(9), 3065-3070.
[14]	Kalumuck, K.E., Fallon, L.F., Jr., Piotrowski, N.A., Rizzo, C.M.D., Carson, C.C. and Irons-Georges, T. (1998) Magill’s medical guide. Revised Edition, Salem Press, Hackensack, 221.
[15]	Tindall, K.R. and Kunkel, T.A. (1988) Fidelity of DNA synthesis by the Thermus aquaticus DNA polymerase. Biochemistry, 27, 6008-6013.
[16]	Messier, W. and Stewart, C.-B. (1997) Episodic adaptive evolution of primate lysozymes. Nature, 385(6612), 151- 154.
[17]	Prusiner, S.B. (1997) Prion diseases and the BSE crisis. Science, 278(5336), 245-251.