DNA aptamers detecting generic amyloid epitopes.

Amyloids are fibrillar protein aggregates resulting from non-covalent autocatalytic polymerization of various structurally and functionally unrelated proteins. Previously we have selected DNA aptamers, which bind specifically to the in vitro assembled amyloid fibrils of the yeast prionogenic protein Sup35. Here we show that such DNA aptamers can be used to detect SDS-insoluble amyloid aggregates of the Sup35 protein, and of some other amyloidogenic proteins, including mouse PrP, formed in yeast cells. The obtained data suggest that these aggregates and the Sup35 amyloid fibrils assembled in vitro possess common conformational epitopes recognizable by aptamers. The described DNA aptamers may be used for detection of various amyloid aggregates in yeast and, presumably, other organisms.

Proteinase B disruption is required for high level production of human mechano-growth factor in Saccharomyces cerevisiae.

Mechano-growth factor (MGF) is a product of a unique muscle-specific splice variant of the insulin-like growth factor I gene. Potential use of MGF to improve regenerative capability of skeletal muscle as well as to prevent neuronal damage has been widely discussed. Human MGF was expressed in Saccharomyces cerevisiae, but the yield of the recombinant protein was low due to its rapid degradation. The proteinase B was identified as the enzyme responsible for MGF processing. A yeast strain with Deltaprb1 deletion was created resulting in a fivefold increase of MGF yield that reached 50 mg/l. The biological activity of recombinant MGF was verified in a proliferation assay employing human postnatal myoblasts.