DELETION ANALYSIS OF THE ESCHERICHIA-COLI RHO-DEPENDENT TRANSCRIPTIONTERMINATOR TRP-T'

We have analyzed with deletion mutations the Escherichia coli rho-depe ndent transcription terminator trp t'. This site, 211 nucleotides in l ength, contains multiple sequence elements that are recognized by rho. Among these multiple elements are two that together appear to be impo rtant for full transcription termination efficiency in vitro and are s imilar to the rutA and rutB sequence elements in the lambdatR1 rho-dep endent terminator previously described by Chen and Richardson (1987). The results suggest for the first time that common functionally import ant elements are shared among rho-dependent terminators. Other regions of trp t' also appear to contribute to its functional efficiency, con sistent with the idea that rho-dependent terminators contain dispersed and redundant recognition segments.