(A) Growth curves of wild type and puf3Δ
strains following switch to glucose depletion medium (YPGE).
(B) The abundance of mitochondrial proteins was assessed in WT and
puf3Δ strains at the indicated time points following
switch to glucose depletion medium (YPGE). Western blot analysis of Por1p
(mitochondrial porin) and Cox2p (subunit II of cytochrome c oxidase) indicate
abundance of mitochondrial proteins; Pgk1p (phosphoglycerate kinase) serves as a
loading control.
(C) Schematic representation of the domain structure of Puf3p.
“*” indicates identified phosphorylation sites. “A or
D” denote serine or threonine residues that were mutated to alanine or
aspartate. The PUF domain mediates mRNA-binding.
(D) Growth curves of WT and the indicated Puf3p mutants in glucose
depletion medium.
(E) Mitochondrial biogenesis is severely compromised in the
Puf3p(24A) mutant. Possible phosphorylation of Puf3p, Puf3p(24A), Puf3p(24D),
and Puf3p(24A PUF domainΔ) at the indicated times following glucose
depletion was assessed by Western blot using FLAG-tagged versions of these
proteins. The 24A PUF domainΔ protein runs at a smaller size but the gel
was cropped to show the relevant band. The accumulation of mitochondrial
proteins was assessed in the same samples by Western blot. Por1p and Cox2p are
mitochondrial markers, Pgk1p is loading control.
(F) The Puf3p(24A) mutant acts as a dominant negative. Growth curves
of the indicated diploid strains: +/+ (WT), +/puf3Δ and
+/PUF3(24A) following switch to glucose depletion medium.
(G) Mitochondrial biogenesis following glucose depletion in the
indicated strains was assayed by Western blot.