FIG. 4.

Northern analysis of insAB′ mRNA. Total RNAs extracted from cells growing exponentially in LB and induced as shown were resolved by formaldehyde-agarose gel electrophoresis, transferred to nylon membranes, and hybridized with ³³P-labeled insAB′ DNA. The amount of Δhns RNA loaded was 0.66 times that of hns⁺ RNA (10 μg) to compensate for the lower proportion of rRNA present in hns mutant cells (20). The arrowhead indicates the position of the insAB′ mRNA. The scale on the right is derived from a ³³P-labeled 1-kb DNA ladder (Gibco-BRL) denatured and processed with the RNAs.