|
Marijana Radonjic, Jean-Christophe Andrau, Patrick
P.C.W. Kemmeren, Philip Lijnzaad, Dik van Leenen, Frank C.P.
Holstege. Genomics Laboratory, UMC Utrecht, Universiteitsweg 100,
Utrecht, 3584 CG, The Netherlands.
We are studying S.cerevisiae stationary phase (SP) as a model for
quiescence. Initial goals are to determine SP-specific genes and
investigate how the transcriptional program of SP is regulated. A 34
time-point microarray experiment covering SP exit, mid-log, diauxic
shift and entry into SP was performed. To determine mRNA changes per
cell, an external normalisation approach was applied. This reveals
dramatic changes in the mRNA population across the time series, with
rapid induction of genes upon SP exit and rapid decay prior to
diauxic shift. This is followed by partial recovery and a slow decay
phase upon SP entry. Despite the global mRNA downregulation in SP,
460 genes are induced in SP relative to the other genes. Most of
these are already induced during diauxic shift, with only a fraction
showing solely SP-specific induction. Phenotype analysis of 16 genes
whose mRNA levels change in agreement with a putative role in SP,
confirmed their requirement for SP. The rapid induction of genes
upon SP exit indicates that the transcription machinery is
maintained throughout SP, poised for rapid growth. To investigate
this further, genome-wide location analysis (ChIP on chip) for RNA
polymerase II was carried out, revealing dramatic re-localisation
during exit and entry from SP as well as evidence for transcription
during SP. The microarray data and follow up experiments provide a
framework for further investigating how entry and exit from SP is
regulated through transcription.
Program Nr. 379A from 2004 Yeast meeting |
