Background: Xrn1 exoribonuclease is the major mRNA degradation enzyme
in Saccharomyces cerevisiae. In exponentially growing cells, Xrn1 is
localised in the yeast cells and directs the degradation of mRNA molecules. Xrn1
is gradually deposited and presumably inactivated in the processing bodies
(P-bodies) as the yeast population ages. Xrn1 can also localise to the membrane
compartment of the arginine permease Can1/eisosome compartment at the yeast
plasma membrane. This localisation correlates with the metabolic (diauxic) shift
from glucose fermentation to respiration, although the relevance of this Xrn1
localisation remains unknown. Methods: We monitored the growth rates and
morphology of Xrn1-green fluorescent protein (GFP) cells compared to wild-type
and