FIG. 2.

Increased groESL mRNA levels in a ς³²-overexpressing C. crescentus strain. (A) An 18-nucleotide primer complementary to nucleotides −15 to +3 of the 5′ region of the groESL operon was 5′ end labelled and hybridized to 50 μg of total RNA isolated from NA1000 cells carrying (lanes 2 and 4) or not carrying (lanes 1 and 3) the plasmid pAR33 (high-copy-number plasmid containing C. crescentus rpoH gene) grown at 30°C or exposed to 42°C for 15 min. The hybrids were then extended by using reverse transcriptase, and the extension products were resolved by denaturing gel electrophoresis and autoradiography. (B) Sequence of the 5′ region of the groESL operon. The transcription start site is shown by an arrow over the nucleotide sequence. The putative −10 and −35 regions of the P2 promoter are underlined. The ATG of the initiator methionine is shown in bold type. The oligonucleotide used in primer extension experiments is complementary to the sequence underlined twice.