Yeast 2005; 22: 385–399.
Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/yea.1218
SFP1 is involved in cell size modulation in
respiro-fermentative growth conditions
Chiara Cipollina, Lilia Alberghina, Danilo Porro* and Marina Vai
Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Piazza della Scienza 2, 20126, Milano, Italy
Danilo Porro, Dipartimento di
Biotecnologie e Bioscienze,
Università degli Studi di
Milano-Bicocca, Piazza della
Scienza 2, 20126, Milano, Italy.
Received: 27 July 2004
Accepted: 28 December 2004
Saccharomyces cerevisiae grows fast on glucose, while growth slows down on ethanol
as cells move from glucose fermentation to oxidative metabolism. The type of carbon
source influences both the specific growth rate and cell cycle progression, as well as
cell size. Yeast cells grown on glucose have a larger size than cells grown on ethanol.
Here, we analysed the behaviour of a sfp1. nul.l mutant during balanced and transitory
states of growth in batch in response to changes in the growth medium carbon sources.
In a screening for mutants affected in cell size at Start, SFP1 has been identified as
a gene whose deletion caused one of the smallest whi phenotype. Findings presented
in this work indicate that in the sfp1 null mutant the reduction in cell size is not
only a consequence of the reduced growth rate but it is tightly linked to the cellular
metabolism. The SFP1 gene product is required to sustain the increase of both rRNA
and protein content that in wild-type cells takes place in respiro-fermentative growth
conditions, while it seems dispensable for growth on non-fermentable carbon sources.
It follows that sfp1 cells growing on ethanol have a larger size than cells growing on
glucose and, noticeably, the former enter the S phase with a critical cell size higher
than the latter. These features, combined with the role of Sfp1p as a transcriptional