THE YEAST 2-HYBRID SYSTEM DETECTS INTERACTIONS BETWEEN BACILLUS-SUBTILIS SIGMA(B) REGULATORS

sigma(B), the general stress response a factor of Bacillus subtilis, i s regulated by the products of seven genes (rsbR, S, T, U, V, W, and X ) with which it is cotranscribed. Biochemical techniques previously re vealed physical associations among RsbW, RsbV, and sigma(B) but failed to detect interactions of RsbR, S, T, U, or X with each other or RsbV , RsbW, or sigma(B). Using the yeast two-hybrid system, we have non ob tained evidence for such interactions. The yeast reporter system was a ctivated when RsbS was paired with either RsbR or RsbT, RsbR was paire d with RsbT, and RsbV was paired with either RsbU or RsbW, In addition , RsbW(2) and RsbR(2) dimer formation was detected, RsbX failed to sho w interactions with itself or any of the other sigB operon products.