A news item reports on the discovery by two different labs of microRNAs in single-celled green algae.
This paper from Peter Tessier and Susan Lindquist at the Whitehead Institute for Biomedical Research demonstrates that particular sequence elements appear necessary to switch proteins to their prion state. There's also a perspective piece on prion studies from Witold Surewicz at Case Western Reserve University.
Another paper, this one from lead authors Brian Yeh and Robert Rutigliano, explores the hypothesis that the evolution of new guanine nucleotide exchange factors provides "a mechanism for linking the core cytoskeletal machinery to a wide range of new control inputs."