Could a bee sting cause scrapie?
Yes, indeed — there was an apparent near miss 23.6 million years ago in a common ancestor of sheep and cow — a retrotransposon event that might have boosted prion protein production to levels fostering sporadic TSE. Ruminants contain a 1220 bp mariner retrotransposon in their 3′ UTR portion of their mRNA. This element, with its terminal inverted repeats, are described by Lee as a fossil transposase pseudogene with homology to the Mellifera (bee) subfamily. It is probably an old insertion shared by all ruminants since it has 7-8 frameshifts and 5 stop condons — figure 3 of the Lee paper shows a guided translation and the correct flanking human gene alignment. The insertion in cow/sheep occured between 27587 and 27588 in terms of human 3′ UTR numbering, just downstream of the Bov-tA3, greatly increasing the length of ruminant mRNA. Dating the 3 retrotransposon insertions in ruminant prion 3′ UTR mRNA is accomplished by simply aligning cow and sheep 3′ UTR mRNA sequences in ClustalW an
