A few days ago, I donated blood for the first time in many years, having been excluded becauseof residence in Britain during the 1980s for reason of exposure to beef taintedwith bovine spongiform encephalitis (BSE), the mad cow disease.
BSE is a #prion disease similar to Scrapie in sheep and
chronic wasting disease(CWD) in deer. In humans, prions cause Creutzfeldt-Jakob disease (CJD) and Kuru.
Whereas most infectious diseases are transmitted via living bacterial or fungal cells, or in the case or viruses by a genetic blueprint (DNA or RNA) that tells the host cell how to replicate the virus, prions contain no genetic material. A prions is a protein that misfold into a self-promoting conformation that causes other copies of the same protein to misfold in the same way. In the diseases mentioned above, the protein is called PrP. It is found in normal nerve tissue folded in its “normal” conformation, purpose not clear. On misfolding, the aberrant PrP forms accumulate to form amyloid plaques that cause neurological damage.
BSE is thought to have spread via recycling of animal waste in cattle feed. In humans, the parallel increase in CJD was feared to have arisen from eating beef containing misfolded bovine PrP.
But there are other prionproteins besides PrP. This got me thinking, do plants have prions too? The Internet provided a quick example: a protein called Luminidependens (LD) has been identified in Arabidopsis, a cress popular in plant research. LD plays a role in photoperiodism, responding to daylength to control flowering time (see Leaf38 “Let Chrysanthemums sleep”, https://lnkd.in/eJUyhrFS). Cloned into yeast, LD behaves like a prion, adopting different self-promoting conformations. Changes in LD folding might serve as anon-genetic memory that could affect the way the plant flowers. Mechanisms like this could explain inheritance of traits without the involvement of any DNA or RNA.
Further reading
🥨 Gottlieb S (1999) FDA bans blooddonation by people who have lived in UK. BMJ 319(7209), 535. https://doi.org/10.1136/bmj.319.7209.535
🥨 Wikipedia (2024) Prion, https://en.wikipedia.org/w/index.php?title=Prion&oldid=1233676695
🥨 Chakrabortee S et al(2016). Luminidependens (LD) is an Arabidopsis protein with prionbehavior. Proc. Natl. Acad. Sci. 113(21), 6065–6070. https://doi.org/10.1073/pnas.1604478113
🥨 Nowogrodzki A. (2016) Plant protein behaves like a prion. Nature (2016). https://doi.org/10.1038/nature.2016.19824
