Scrapie strain-specific interactions with endogenous murine leukaemia virus.

Abstract

The finding that a senescence-accelerated mouse (SAMP8) shows early brain ageing, with histopathological changes resembling those seen in scrapie, combined with the discovery of high levels of endogenous murine leukaemia virus (MuLV) in brains of SAMP8 mice prompted us to examine the effect of scrapie infection on MuLV titres in this strain and in one of its progenitors, the AKR strain. Three scrapie strains (ME7, 22L and 139A) that had a comparatively short incubation period in SAMP8 and AKR mice caused an increase in brain MuLV titres that was scrapie strainspecific : in each mouse strain, the greatest effect was with 139A, and the least with ME7. The 22A scrapie strain, which has a long incubation period in SAMP8 mice, did not affect MuLV titres in brains of this mouse strain. Previous analyses of scrapie incubation periods in AKR, SAMP8 and another strain derived from an AKR cross (SAMR1) showed an inverse relationship between brain MuLV titres and scrapie incubation periods. This finding, combined with the effect of scrapie on MuLV titres, suggests an interaction between the scrapie infectious process and MuLV replication.

Expression Profiles of Endogenous Retroviruses in Old World Monkeys

“…In the case of schizophrenia, however, the results are not unequivocal (14). In mice, there is also evidence of involvement of ERVs in spongiform encephalopathies (10). Thus, the higher expression of HERVs in the brain may have implications for susceptibility to neurological diseases and runs contrary to the apparent suppression of expression of even recent elements, such as GaLV in nonhuman primates.…”

“…Thus, at the DNA level, HERV evolution involves both vertical transmission and de novo integration of elements by retrotransposition or reinfection, whether looking within or among species (3,4,26). However, the majority of elements integrated before the OWM and great ape lineages diverged and thus have a similar genomic distribution pattern among catarrhines (16,10,27).…”

The Prion Protein Has RNA Binding and Chaperoning Properties Characteristic of Nucleocapsid Protein NCp7 of HIV-1

“…One picomole of RNA was used, and the molar ratios of protein to nt are indicated at the top. Lanes 1,5,9,13,17 (Fig. 1).…”

“…In addition, PrP was shown to interact with sulfated glycans (12), RNA aptamers (13), and large nucleic acids (14,15), causing the formation of nucleoprotein complexes similar to HIV-1 nucleocapsid-RNA complexes formed in vitro (16). A recent report shows that MuLV replication accelerates the scrapie infectious process (17), suggesting possible in vivo interactions between retroviruses and PrP.…”

Small-Ruminant Lentivirus Enhances PrP Sc Accumulation in Cultured Sheep Microglial Cells

“…Interestingly, recombinant prion protein has demonstrated the abilities to bind and to chaperone retroviral RNA, which are similar to retroviral nucleocapsid's function (18,19,42). Other interactions between prion protein and retroviruses have been identified; these interactions include an increase in murine leukemia virus (MLV) titers and replication and a shortened scrapie incubation period in the brains of coinfected mice (12,40). In vitro coinfection studies have also demonstrated increased scrapie infectivity release into the cell culture supernatant in murine cell cultures coinfected with MLV (39).…”