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le jeudi 11 mars à 11:00

Pierre NICOLAS (MIG, INRA, 78350 Jouy en Josas)

Salle de l’UFR (Bat. Mendel, 5eme étage)

par Vincent Daubin - 11 mars 2010

Genome-scale transcriptional activity of Bacillus subtilis cells under various life styles.

Microorganisms rely largely on changes of the transcriptional activity
to adapt to the variations of the environment. However, it has not be
possible until recently to obtain a knowledge of the transcriptional
activity that could compare with the completeness of the genome
sequences. Ideally the data should be unbiased with respect to the set
of conditions, as well as with respect to the segments of chromosome
whose transcription is assessed. The oligonucleotide tiling array
technology provides this opportunity and was used in this work to
quantify the transcriptional activity of B. subtilis. A set of 97
conditions (240 hybridizations) were explored to provide the broadest
coverage of the biology of the bacterium. As a validation of our
experimental design, we observed that most known genes belonged to the
highly expressed ones in at least one condition. The data allowed the
precise and systematic mapping of the transcribed regions and of the
changes in transcriptional activity of B. subtilis.

Here we will present our main findings concerning the architecture of
transcriptional control in this versatile bacterium.
We will also present two distinct statistical models motivated by the
analysis of this data. The purpose of the first model is to improve the
processing of the hybridization signal with a hidden-Markov model. The
second model intends to relate the expression data to the presence of
sequence motifs in the genome with a transdimensional MCMC algorithm.

A Basysbio/Bacell SysMO collaborative work.