(A, B) RT-PCR (A) and qPCR (B) reveal that the TOR-sensitive
MEP2 gene transcription by Gln3 is enhanced in
anticodon modification mutants that lack Elongator and U34 thiolation
activities. Total RNA was isolated from the indicated strains cultivated
with good nitrogen source (glutamine) supply in the absence (-) or presence
(+) of 50 mM (rap) rapamycin. Following RT-PCR, the transcriptional
induction of the MEP2 gene was analysed in comparison to
actin (ACT1) transcription (A) and quantified by qPCR in
relation to ALG9 transcription (B) (mean values of
triplicates).
(C) Gln3 mislocalises to the nucleus in an
elp3∆ Elongator mutant, a property suppressible by tRNA
overexpression. Wild-type cells carrying pRS416-GFP-Gln3 were grown in
minimal medium containing glutamine (gln) as the sole N-source with or
without 10 nM rapamycin (rap). For localization studies with the Elongator
mutant in response to tRNA overexpression, elp3∆ cells
carrying pRS416-GFP-Gln3 together with empty vector control or multicopy
tRNA plasmid (pQKE) were used and images taken in phase contrast, DAPI- and
GFP-fluorescence modes (phase, DAPI, Gln3-GFP). Arrows indicate nuclear
localization of GFP-tagged Gln3.