(A) Primer extension analysis of clpL2, groES, and grpE mRNAs. Total RNA was extracted from O. oeni cells harvested in the exponential phase (lane C) or after a 30-min shift to 42°C (lane HS). Primer extension products are shown alongside DNA-sequencing reaction products (lanes T, G, C, and A). (B) Nucleotide sequences of the clpL2, groESL, grpE, ctsR, hsp18, clpX, and clpP promoter regions. Potential −35 and −10 sequences are underlined and boldface, transcriptional start points are indicated by +1, and CtsR heptad direct-repeat operator sequences are indicated by arrows. Mutation of the groES promoter performed by insertion of a PstI site in the repeated sequence of the CtsR operator site is indicated.