FIG. 5.

Deletion of PNPase leads to accumulation of 30S, 50S, and 70S ribosomal subunits. The E. coli wild-type and Δpnp cells were transformed with the pINIII plasmid alone as a control. The Δpnp cells were also transformed with the pINIII plasmid containing PNPase, RNase II, or RNase R. The cells growing exponentially at 37°C were cold shocked at 15°C, and samples were collected 72 h after the cold shock. Polysomes were isolated and resolved as described in Materials and Methods.