What is a prion? Specifically, what is known about the molecular
structure of prions and how they cause infections such as
Creutzfeldt-Jakob disease?  Share on Tumblr  Susan Lindquist is
a researcher at the Howard Hughes Medical Institute, located in
the department of molecular genetics and cell biology at the
University of Chicago. She responds:  "'Prion' is a term first
used to describe the mysterious infectious agent responsible for
several neurodegenerative diseases found in mammals, including
Creutzfeldt-Jakob disease (CJD) in humans. The word itself
derives from 'proteinaceous infectious particle'; it refers to
the initially heretical hypothesis that the infectious agent
causing those diseases consists only of protein, with no nucleic
acid genome. (All previously known pathogens, such as bacteria
and viruses, contain nucleic acids, which enable them to
reproduce.) The prion hypothesis explained why the mysterious
infectious agent is resistant to ultraviolet radiation, which
breaks down nucleic acids, bu