XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Posters
45.
THE COMLEX NETWORK REGULATORY CIRCUITS IN THE REGULATION
OF SIGMA faCTORS INVOLVED IN DIffERENTIATION AND STRESS
RESPONSE IN STrePTOMYCES CoeLICOLor A3(2)
Bronislava Řežuchová, Beatrica Ševčíková, Dagmar Homerová and Ján Kormanec
Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21,
845 51 Bratislava, Slovakia
Genome of the gram-positive soil bacterium Streptomyces coelicolor is a twice as large as
the E. coli genome and contains 7 825 genes including 66 genes encoding sigma factors
of RNA polymerase that is the largest number among the so far examined bacteria. In
B. subtilis a general stress response is under the control of a single sigma factor, SigB. Its
gene is located in the operon together with rsbW and rsbV genes. The product of rsbW is
an anti sigma factor of SigB, which serves as serine kinase that binds and phosphorylates
its negative regulator so-called anti-anti sigma factor RsbV. However, genome sequence
analysis in S. coelicolor has shown nine sigB homologues, as well as putative 48 anti-sigma
factors (RsbW homologues) and 18 antagonists of anti-sigma factors (RsbV homologues).
Bacterial two hybrid system was used to investigate and characterize interaction between
nine known homologues SigB and 15 suggested anti-sigma factors, and between these
anti-sigma factors and 9 selected anti-anti sigma factors. This method allows detect even
relatively weak protein-protein interaction. The efficiency of interactions was quantified
by measuring β-galactosidase activities in liquid cultures. The interactions were
confirmed by native PAGE. The results revealed very complex way of regulation, where
several sigma factors interact with different anti-sigma factors that additionally interact
with several subclasses of anti-sigma factor antagonists.
Acknowledgement: This work was supported by the VEGA grant 2/0104/09 from Slovak
Academy of Sciences.
XXII. Biochemistry Congress, Martin
163